The current way of handling refcounting in the DP MST helpers is really
confusing and probably just plain wrong because it's been hacked up many
times over the years without anyone actually going over the code and
seeing if things could be simplified.
To the best of my understanding, the current scheme works like this:
drm_dp_mst_port and drm_dp_mst_branch both have a single refcount. When
this refcount hits 0 for either of the two, they're removed from the
topology state, but not immediately freed. Both ports and branch devices
will reinitialize their kref once it's hit 0 before actually destroying
themselves. The intended purpose behind this is so that we can avoid
problems like not being able to free a remote payload that might still
be active, due to us having removed all of the port/branch device
structures in memory, as per:
commit 91a25e4631 ("drm/dp/mst: deallocate payload on port destruction")
Which may have worked, but then it caused use-after-free errors. Being
new to MST at the time, I tried fixing it;
commit 263efde31f ("drm/dp/mst: Get validated port ref in drm_dp_update_payload_part1()")
But, that was broken: both drm_dp_mst_port and drm_dp_mst_branch structs
are validated in almost every DP MST helper function. Simply put, this
means we go through the topology and try to see if the given
drm_dp_mst_branch or drm_dp_mst_port is still attached to something
before trying to use it in order to avoid dereferencing freed memory
(something that has happened a LOT in the past with this library).
Because of this it doesn't actually matter whether or not we keep keep
the ports and branches around in memory as that's not enough, because
any function that validates the branches and ports passed to it will
still reject them anyway since they're no longer in the topology
structure. So, use-after-free errors were fixed but payload deallocation
was completely broken.
Two years later, AMD informed me about this issue and I attempted to
come up with a temporary fix, pending a long-overdue cleanup of this
library:
commit c54c7374ff ("drm/dp_mst: Skip validating ports during destruction, just ref")
But then that introduced use-after-free errors, so I quickly reverted
it:
commit 9765635b30 ("Revert "drm/dp_mst: Skip validating ports during destruction, just ref"")
And in the process, learned that there is just no simple fix for this:
the design is just broken. Unfortunately, the usage of these helpers are
quite broken as well. Some drivers like i915 have been smart enough to
avoid accessing any kind of information from MST port structures, but
others like nouveau have assumed, understandably so, that
drm_dp_mst_port structures are normal and can just be accessed at any
time without worrying about use-after-free errors.
After a lot of discussion, me and Daniel Vetter came up with a better
idea to replace all of this.
To summarize, since this is documented far more indepth in the
documentation this patch introduces, we make it so that drm_dp_mst_port
and drm_dp_mst_branch structures have two different classes of
refcounts: topology_kref, and malloc_kref. topology_kref corresponds to
the lifetime of the given drm_dp_mst_port or drm_dp_mst_branch in it's
given topology. Once it hits zero, any associated connectors are removed
and the branch or port can no longer be validated. malloc_kref
corresponds to the lifetime of the memory allocation for the actual
structure, and will always be non-zero so long as the topology_kref is
non-zero. This gives us a way to allow callers to hold onto port and
branch device structures past their topology lifetime, and dramatically
simplifies the lifetimes of both structures. This also finally fixes the
port deallocation problem, properly.
Additionally: since this now means that we can keep ports and branch
devices allocated in memory for however long we need, we no longer need
a significant amount of the port validation that we currently do.
Additionally, there is one last scenario that this fixes, which couldn't
have been fixed properly beforehand:
- CPU1 unrefs port from topology (refcount 1->0)
- CPU2 refs port in topology(refcount 0->1)
Since we now can guarantee memory safety for ports and branches
as-needed, we also can make our main reference counting functions fix
this problem by using kref_get_unless_zero() internally so that topology
refcounts can only ever reach 0 once.
Changes since v4:
* Change the kernel-figure summary for dp-mst/topology-figure-1.dot a
bit - danvet
* Remove figure numbers - danvet
Changes since v3:
* Remove rebase detritus - danvet
* Split out purely style changes into separate patches - hwentlan
Changes since v2:
* Fix commit message - checkpatch
* s/)-1/) - 1/g - checkpatch
Changes since v1:
* Remove forward declarations - danvet
* Move "Branch device and port refcounting" section from documentation
into kernel-doc comments - danvet
* Export internal topology lifetime functions into their own section in
the kernel-docs - danvet
* s/@/&/g for struct references in kernel-docs - danvet
* Drop the "when they are no longer being used" bits from the kernel
docs - danvet
* Modify diagrams to show how the DRM driver interacts with the topology
and payloads - danvet
* Make suggested documentation changes for
drm_dp_mst_topology_get_mstb() and drm_dp_mst_topology_get_port() -
danvet
* Better explain the relationship between malloc refs and topology krefs
in the documentation for drm_dp_mst_topology_get_port() and
drm_dp_mst_topology_get_mstb() - danvet
* Fix "See also" in drm_dp_mst_topology_get_mstb() - danvet
* Rename drm_dp_mst_topology_get_(port|mstb)() ->
drm_dp_mst_topology_try_get_(port|mstb)() and
drm_dp_mst_topology_ref_(port|mstb)() ->
drm_dp_mst_topology_get_(port|mstb)() - danvet
* s/should/must in docs - danvet
* WARN_ON(refcount == 0) in topology_get_(mstb|port) - danvet
* Move kdocs for mstb/port structs inline - danvet
* Split drm_dp_get_last_connected_port_and_mstb() changes into their own
commit - danvet
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-7-lyude@redhat.com
For a lot of use cases we need 64bit sequence numbers. Currently drivers
overload the dma_fence structure to store the additional bits.
Stop doing that and make the sequence number in the dma_fence always
64bit.
For compatibility with hardware which can do only 32bit sequences the
comparisons in __dma_fence_is_later only takes the lower 32bits as significant
when the upper 32bits are all zero.
v2: change the logic in __dma_fence_is_later
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Link: https://patchwork.freedesktop.org/patch/266927/
This reverts commit 9a09a42369.
The whole interface isn't thought through. Since this function can't
fail we actually can't allocate an object to store the sync point.
Sorry, I should have taken the lead on this from the very beginning and
reviewed it more thoughtfully. Going to propose a new interface as a
follow up change.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Link: https://patchwork.freedesktop.org/patch/265580/
The TFU can copy from raster, UIF, and SAND input images to UIF output
images, with optional mipmap generation. This will certainly be
useful for media EGL image input, but is also useful immediately for
mipmap generation without bogging the V3D core down.
For now we only run the queue 1 job deep, and don't have any hang
recovery (though I don't think we should need it, with TFU). Queuing
multiple jobs in the HW will require synchronizing the YUV coefficient
regs updates since they don't get FIFOed with the job.
v2: Change the ioctl to IOW instead of IOWR, always set COEF0, explain
why TFU is AUTH, clarify the syncing docs, drop the unused TFU
interrupt regs (you're expected to use the hub's), don't take
&bo->base for NULL bos.
v3: Fix a little whitespace alignment (noticed by checkpatch), rebase
on drm_sched_job_cleanup() changes.
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Dave Emett <david.emett@broadcom.com> (v2)
Link: https://patchwork.freedesktop.org/patch/264607/
This patch adds a couple of helpers to remove the boilerplate involved
in grabbing all of the modeset locks.
I've also converted the obvious cases in drm core to use the helpers.
The only remaining instance of drm_modeset_lock_all_ctx() is in
drm_framebuffer. It's complicated by the state clear that occurs on
deadlock. ATM, there's no way to inject code in the deadlock path with
the helpers, so it's unfit for conversion.
Changes in v2:
- Relocate ret argument to the end of the list (Daniel)
- Incorporate Daniel's doc suggestions (Daniel)
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181129150423.239081-4-sean@poorly.run
drm-misc-next for v4.21:
Core Changes:
- Merge drm_info.c into drm_debugfs.c
- Complete the fake drm_crtc_commit's hw_done/flip_done sooner.
- Remove deprecated drm_obj_ref/unref functions. All drivers use get/put now.
- Decrease stack use of drm_gem_prime_mmap.
- Improve documentation for dumb callbacks.
Driver Changes:
- Add edid support to virtio.
- Wait on implicit fence in meson and sun4i.
- Add support for BGRX8888 to sun4i.
- Preparation patches for sun4i driver to start supporting linear and tiled YUV formats.
- Add support for HDMI 1.4 4k modes to meson, and support for VIC alternate timings.
- Drop custom dumb_map in vkms.
- Small fixes and cleanups to v3d.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/151a3270-b1be-ed75-bd58-6b29d741f592@linux.intel.com
Pull dma-mapping fixes from Christoph Hellwig:
"Two dma-direct / swiotlb regressions fixes:
- zero is a valid physical address on some arm boards, we can't use
it as the error value
- don't try to cache flush the error return value (no matter what it
is)"
* tag 'dma-mapping-4.20-3' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: Skip cache maintenance on map error
dma-direct: Make DIRECT_MAPPING_ERROR viable for SWIOTLB
Pull XArray updates from Matthew Wilcox:
"We found some bugs in the DAX conversion to XArray (and one bug which
predated the XArray conversion). There were a couple of bugs in some
of the higher-level functions, which aren't actually being called in
today's kernel, but surfaced as a result of converting existing radix
tree & IDR users over to the XArray.
Some of the other changes to how the higher-level APIs work were also
motivated by converting various users; again, they're not in use in
today's kernel, so changing them has a low probability of introducing
a bug.
Dan can still trigger a bug in the DAX code with hot-offline/online,
and we're working on tracking that down"
* tag 'xarray-4.20-rc4' of git://git.infradead.org/users/willy/linux-dax:
XArray tests: Add missing locking
dax: Avoid losing wakeup in dax_lock_mapping_entry
dax: Fix huge page faults
dax: Fix dax_unlock_mapping_entry for PMD pages
dax: Reinstate RCU protection of inode
dax: Make sure the unlocking entry isn't locked
dax: Remove optimisation from dax_lock_mapping_entry
XArray tests: Correct some 64-bit assumptions
XArray: Correct xa_store_range
XArray: Fix Documentation
XArray: Handle NULL pointers differently for allocation
XArray: Unify xa_store and __xa_store
XArray: Add xa_store_bh() and xa_store_irq()
XArray: Turn xa_erase into an exported function
XArray: Unify xa_cmpxchg and __xa_cmpxchg
XArray: Regularise xa_reserve
nilfs2: Use xa_erase_irq
XArray: Export __xa_foo to non-GPL modules
XArray: Fix xa_for_each with a single element at 0
Pull HID fixes from Jiri Kosina:
- revert of the high-resolution scrolling feature, as it breaks certain
hardware due to incompatibilities between Logitech and Microsoft
worlds. Peter Hutterer is working on a fixed implementation. Until
that is finished, revert by Benjamin Tissoires.
- revert of incorrect strncpy->strlcpy conversion in uhid, from David
Herrmann
- fix for buggy sendfile() implementation on uhid device node, from
Eric Biggers
- a few assorted device-ID specific quirks
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid:
Revert "Input: Add the `REL_WHEEL_HI_RES` event code"
Revert "HID: input: Create a utility class for counting scroll events"
Revert "HID: logitech: Add function to enable HID++ 1.0 "scrolling acceleration""
Revert "HID: logitech: Enable high-resolution scrolling on Logitech mice"
Revert "HID: logitech: Use LDJ_DEVICE macro for existing Logitech mice"
Revert "HID: logitech: fix a used uninitialized GCC warning"
Revert "HID: input: simplify/fix high-res scroll event handling"
HID: Add quirk for Primax PIXART OEM mice
HID: i2c-hid: Disable runtime PM for LG touchscreen
HID: multitouch: Add pointstick support for Cirque Touchpad
HID: steam: remove input device when a hid client is running.
Revert "HID: uhid: use strlcpy() instead of strncpy()"
HID: uhid: forbid UHID_CREATE under KERNEL_DS or elevated privileges
HID: input: Ignore battery reported by Symbol DS4308
HID: Add quirk for Microsoft PIXART OEM mouse
Pull networking fixes from David Miller:
1) Need to take mutex in ath9k_add_interface(), from Dan Carpenter.
2) Fix mt76 build without CONFIG_LEDS_CLASS, from Arnd Bergmann.
3) Fix socket wmem accounting in SCTP, from Xin Long.
4) Fix failed resume crash in ena driver, from Arthur Kiyanovski.
5) qed driver passes bytes instead of bits into second arg of
bitmap_weight(). From Denis Bolotin.
6) Fix reset deadlock in ibmvnic, from Juliet Kim.
7) skb_scrube_packet() needs to scrub the fwd marks too, from Petr
Machata.
8) Make sure older TCP stacks see enough dup ACKs, and avoid doing SACK
compression during this period, from Eric Dumazet.
9) Add atomicity to SMC protocol cursor handling, from Ursula Braun.
10) Don't leave dangling error pointer if bpf_prog_add() fails in
thunderx driver, from Lorenzo Bianconi. Also, when we unmap TSO
headers, set sq->tso_hdrs to NULL.
11) Fix race condition over state variables in act_police, from Davide
Caratti.
12) Disable guest csum in the presence of XDP in virtio_net, from Jason
Wang.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (64 commits)
net: gemini: Fix copy/paste error
net: phy: mscc: fix deadlock in vsc85xx_default_config
dt-bindings: dsa: Fix typo in "probed"
net: thunderx: set tso_hdrs pointer to NULL in nicvf_free_snd_queue
net: amd: add missing of_node_put()
team: no need to do team_notify_peers or team_mcast_rejoin when disabling port
virtio-net: fail XDP set if guest csum is negotiated
virtio-net: disable guest csum during XDP set
net/sched: act_police: add missing spinlock initialization
net: don't keep lonely packets forever in the gro hash
net/ipv6: re-do dad when interface has IFF_NOARP flag change
packet: copy user buffers before orphan or clone
ibmvnic: Update driver queues after change in ring size support
ibmvnic: Fix RX queue buffer cleanup
net: thunderx: set xdp_prog to NULL if bpf_prog_add fails
net/dim: Update DIM start sample after each DIM iteration
net: faraday: ftmac100: remove netif_running(netdev) check before disabling interrupts
net/smc: use after free fix in smc_wr_tx_put_slot()
net/smc: atomic SMCD cursor handling
net/smc: add SMC-D shutdown signal
...
tpacket_snd sends packets with user pages linked into skb frags. It
notifies that pages can be reused when the skb is released by setting
skb->destructor to tpacket_destruct_skb.
This can cause data corruption if the skb is orphaned (e.g., on
transmit through veth) or cloned (e.g., on mirror to another psock).
Create a kernel-private copy of data in these cases, same as tun/tap
zerocopy transmission. Reuse that infrastructure: mark the skb as
SKBTX_ZEROCOPY_FRAG, which will trigger copy in skb_orphan_frags(_rx).
Unlike other zerocopy packets, do not set shinfo destructor_arg to
struct ubuf_info. tpacket_destruct_skb already uses that ptr to notify
when the original skb is released and a timestamp is recorded. Do not
change this timestamp behavior. The ubuf_info->callback is not needed
anyway, as no zerocopy notification is expected.
Mark destructor_arg as not-a-uarg by setting the lower bit to 1. The
resulting value is not a valid ubuf_info pointer, nor a valid
tpacket_snd frame address. Add skb_zcopy_.._nouarg helpers for this.
The fix relies on features introduced in commit 52267790ef ("sock:
add MSG_ZEROCOPY"), so can be backported as is only to 4.14.
Tested with from `./in_netns.sh ./txring_overwrite` from
http://github.com/wdebruij/kerneltools/tests
Fixes: 69e3c75f4d ("net: TX_RING and packet mmap")
Reported-by: Anand H. Krishnan <anandhkrishnan@gmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
On every iteration of net_dim, the algorithm may choose to
check for the system state by comparing current data sample
with previous data sample. After each of these comparison,
regardless of the action taken, the sample used as baseline
is needed to be updated.
This patch fixes a bug that causes DIM to take wrong decisions,
due to never updating the baseline sample for comparison between
iterations. This way, DIM always compares current sample with
zeros.
Although this is a functional fix, it also improves and stabilizes
performance as the algorithm works properly now.
Performance:
Tested single UDP TX stream with pktgen:
samples/pktgen/pktgen_sample03_burst_single_flow.sh -i p4p2 -d 1.1.1.1
-m 24:8a:07:88:26:8b -f 3 -b 128
ConnectX-5 100GbE packet rate improved from 15-19Mpps to 19-20Mpps.
Also, toggling between profiles is less frequent with the fix.
Fixes: 8115b750db ("net/dim: use struct net_dim_sample as arg to net_dim")
Signed-off-by: Tal Gilboa <talgi@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull USB fixes from Greg KH:
"Here are a number of small USB fixes for 4.20-rc4.
There's the usual xhci and dwc2/3 fixes as well as a few minor other
issues resolved for problems that have been reported. Full details are
in the shortlog.
All have been in linux-next for a while with no reported issues"
* tag 'usb-4.20-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
usb: cdc-acm: add entry for Hiro (Conexant) modem
usb: xhci: Prevent bus suspend if a port connect change or polling state is detected
usb: core: Fix hub port connection events lost
usb: dwc3: gadget: fix ISOC TRB type on unaligned transfers
Revert "usb: gadget: ffs: Fix BUG when userland exits with submitted AIO transfers"
usb: dwc2: pci: Fix an error code in probe
usb: dwc3: Fix NULL pointer exception in dwc3_pci_remove()
xhci: Add quirk to workaround the errata seen on Cavium Thunder-X2 Soc
usb: xhci: fix timeout for transition from RExit to U0
usb: xhci: fix uninitialized completion when USB3 port got wrong status
xhci: Add check for invalid byte size error when UAS devices are connected.
xhci: handle port status events for removed USB3 hcd
xhci: Fix leaking USB3 shared_hcd at xhci removal
USB: misc: appledisplay: add 20" Apple Cinema Display
USB: quirks: Add no-lpm quirk for Raydium touchscreens
usb: quirks: Add delay-init quirk for Corsair K70 LUX RGB
USB: Wait for extra delay time after USB_PORT_FEAT_RESET for quirky hub
usb: dwc3: gadget: Properly check last unaligned/zero chain TRB
usb: dwc3: core: Clean up ULPI device
This reverts commit aaf9978c3c.
Quoting Peter:
There is a HID feature report called "Resolution Multiplier"
Described in the "Enhanced Wheel Support in Windows" doc and
the "USB HID Usage Tables" page 30.
http://download.microsoft.com/download/b/d/1/bd1f7ef4-7d72-419e-bc5c-9f79ad7bb66e/wheel.docxhttps://www.usb.org/sites/default/files/documents/hut1_12v2.pdf
This was new for Windows Vista, so we're only a decade behind here. I only
accidentally found this a few days ago while debugging a stuck button on a
Microsoft mouse.
The docs above describe it like this: a wheel control by default sends
value 1 per notch. If the resolution multiplier is active, the wheel is
expected to send a value of $multiplier per notch (e.g. MS Sculpt mouse) or
just send events more often, i.e. for less physical motion (e.g. MS Comfort
mouse).
For the latter, you need the right HW of course. The Sculpt mouse has
tactile wheel clicks, so nothing really changes. The Comfort mouse has
continuous motion with no tactile clicks. Similar to the free-wheeling
Logitech mice but without any inertia.
Note that the doc also says that Vista and onwards *always* enable this
feature where available.
An example HID definition looks like this:
Usage Page Generic Desktop (0x01)
Usage Resolution Multiplier (0x48)
Logical Minimum 0
Logical Maximum 1
Physical Minimum 1
Physical Maximum 16
Report Size 2 # in bits
Report Count 1
Feature (Data, Var, Abs)
So the actual bits have values 0 or 1 and that reflects real values 1 or 16.
We've only seen single-bits so far, so there's low-res and hi-res, but
nothing in between.
The multiplier is available for HID usages "Wheel" and "AC Pan" (horiz wheel).
Microsoft suggests that
> Vendors should ship their devices with smooth scrolling disabled and allow
> Windows to enable it. This ensures that the device works like a regular HID
> device on legacy operating systems that do not support smooth scrolling.
(see the wheel doc linked above)
The mice that we tested so far do reset on unplug.
Device Support looks to be all (?) Microsoft mice but nothing else
Not supported:
- Logitech G500s, G303
- Roccat Kone XTD
- all the cheap Lenovo, HP, Dell, Logitech USB mice that come with a
workstation that I could find don't have it.
- Etekcity something something
- Razer Imperator
Supported:
- Microsoft Comfort Optical Mouse 3000 - yes, physical: 1:4
- Microsoft Sculpt Ergonomic Mouse - yes, physical: 1:12
- Microsoft Surface mouse - yes, physical: 1:4
So again, I think this is really just available on Microsoft mice, but
probably all decent MS mice released over the last decade.
Looking at the hardware itself:
- no noticeable notches in the weel
- low-res: 18 events per 360deg rotation (click angle 20 deg)
- high-res: 72 events per 360deg → matches multiplier of 4
- I can feel the notches during wheel turns
- low-res: 24 events per 360 deg rotation (click angle 15 deg)
- horiz wheel is tilt-based, continuous output value 1
- high-res: 24 events per 360deg with value 12 → matches multiplier of 12
- horiz wheel output rate doubles/triples?, values is 3
- It's a touch strip, not a wheel so no notches
- high-res: events have value 4 instead of 1
a bit strange given that it doesn't actually have notches.
Ok, why is this an issue for the current API? First, because the logitech
multiplier used in Harry's patches looks suspiciously like the Resolution
Multiplier so I think we should assume it's the same thing. Nestor, can you
shed some light on that?
- `REL_WHEEL` is defined as the number of notches, emulated where needed.
- `REL_WHEEL_HI_RES` is the movement of the user's finger in microns.
- `WM_MOUSEWHEEL` (Windows) is is a multiple of 120, defined as "the threshold
for action to be taken and one such action"
https://docs.microsoft.com/en-us/windows/desktop/inputdev/wm-mousewheel
If the multiplier is set to M, this means we need an accumulated value of M
until we can claim there was a wheel click. So after enabling the multiplier
and setting it to the maximum (like Windows):
- M units are 15deg rotation → 1 unit is 2620/M micron (see below). This is
the `REL_WHEEL_HI_RES` value.
- wheel diameter 20mm: 15 deg rotation is 2.62mm, 2620 micron (pi * 20mm /
(360deg/15deg))
- For every M units accumulated, send one `REL_WHEEL` event
The problem here is that we've now hardcoded 20mm/15 deg into the kernel and
we have no way of getting the size of the wheel or the click angle into the
kernel.
In userspace we now have to undo the kernel's calculation. If our click angle
is e.g. 20 degree we have to undo the (lossy) calculation from the kernel and
calculate the correct angle instead. This also means the 15 is a hardcoded
option forever and cannot be changed.
In hid-logitech-hidpp.c, the microns per unit is hardcoded per device.
Harry, did you measure those by hand? We'd need to update the kernel for
every device and there are 10 years worth of devices from MS alone.
The multiplier default is 8 which is in the right ballpark, so I'm pretty
sure this is the same as the Resolution Multiplier, just in HID++ lingo. And
given that the 120 magic factor is what Windows uses in the end, I can't
imagine Logitech rolling their own thing here. Nestor?
And we're already fairly inaccurate with the microns anyway. The MX Anywhere
2S has a click angle of 20 degrees (18 stops) and a 17mm wheel, so a wheel
notch is approximately 2.67mm, one event at multiplier 8 (1/8 of a notch)
would be 334 micron. That's only 80% of the fallback value of 406 in the
kernel. Multiplier 6 gives us 445micron (10% off). I'm assuming multiplier 7
doesn't exist because it's not a factor of 120.
Summary:
Best option may be to simply do what Windows is doing, all the HW manufacturers
have to use that approach after all. Switch `REL_WHEEL_HI_RES` to report in
fractions of 120, with 120 being one notch and divide that by the multiplier
for the actual events. So e.g. the Logitech multiplier 8 would send value 15
for each event in hi-res mode. This can be converted in userspace to
whatever userspace needs (combined with a hwdb there that tells you wheel
size/click angle/...).
Conflicts:
include/uapi/linux/input-event-codes.h -> I kept the new
reserved event in the code, so I had to adapt the revert
slightly
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Harry Cutts <hcutts@chromium.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
drm-misc-next for v4.21, part 2:
UAPI Changes:
- Remove syncobj timeline support from drm.
Cross-subsystem Changes:
- Document canvas provider node in the DT bindings.
- Improve documentation for TPO TPG110 DT bindings.
Core Changes:
- Use explicit state in drm atomic functions.
- Add panel quirk for new GPD Win2 firmware.
- Add DRM_FORMAT_XYUV8888.
- Set the default import/export function in prime to drm_gem_prime_import/export.
- Add a separate drm_gem_object_funcs, to stop relying on dev->driver->*gem* functions.
- Make sure that tinydrm sets the virtual address also on imported buffers.
Driver Changes:
- Support active-low data enable signal in sun4i.
- Fix scaling in vc4.
- Use canvas provider node in meson.
- Remove unused variables in sti and qxl and cirrus.
- Add overlay plane support and primary plane scaling to meson.
- i2c fixes in drm/bridge/sii902x
- Fix mailbox read size in rockchip.
- Spelling fix in panel/s6d16d0.
- Remove unnecessary null check from qxl_bo_unref.
- Remove unused arguments from qxl_bo_pin.
- Fix qxl cursor pinning.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/9c0409e3-a85f-d2af-b4eb-baf1eb8bbae4@linux.intel.com
Jean-Louis reported a TCP regression and bisected to recent SACK
compression.
After a loss episode (receiver not able to keep up and dropping
packets because its backlog is full), linux TCP stack is sending
a single SACK (DUPACK).
Sender waits a full RTO timer before recovering losses.
While RFC 6675 says in section 5, "Algorithm Details",
(2) If DupAcks < DupThresh but IsLost (HighACK + 1) returns true --
indicating at least three segments have arrived above the current
cumulative acknowledgment point, which is taken to indicate loss
-- go to step (4).
...
(4) Invoke fast retransmit and enter loss recovery as follows:
there are old TCP stacks not implementing this strategy, and
still counting the dupacks before starting fast retransmit.
While these stacks probably perform poorly when receivers implement
LRO/GRO, we should be a little more gentle to them.
This patch makes sure we do not enable SACK compression unless
3 dupacks have been sent since last rcv_nxt update.
Ideally we should even rearm the timer to send one or two
more DUPACK if no more packets are coming, but that will
be work aiming for linux-4.21.
Many thanks to Jean-Louis for bisecting the issue, providing
packet captures and testing this patch.
Fixes: 5d9f4262b7 ("tcp: add SACK compression")
Reported-by: Jean-Louis Dupond <jean-louis@dupond.be>
Tested-by: Jean-Louis Dupond <jean-louis@dupond.be>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the overflow buffer removed, we no longer have a unique address
which is guaranteed not to be a valid DMA target to use as an error
token. The DIRECT_MAPPING_ERROR value of 0 tries to at least represent
an unlikely DMA target, but unfortunately there are already SWIOTLB
users with DMA-able memory at physical address 0 which now gets falsely
treated as a mapping failure and leads to all manner of misbehaviour.
The best we can do to mitigate that is flip DIRECT_MAPPING_ERROR to the
other commonly-used error value of all-bits-set, since the last single
byte of memory is by far the least-likely-valid DMA target.
Fixes: dff8d6c1ed ("swiotlb: remove the overflow buffer")
Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
