Inside drm_clients_info, the rcu_read_lock is held to lock
pid_task()->comm. However, within this protected section, a call to
drm_is_current_master is made, which involves a mutex lock in a future
patch. However, this is illegal because the mutex lock might block
while in the RCU read-side critical section.
Since drm_is_current_master isn't protected by rcu_read_lock, we avoid
this by moving it out of the RCU critical section.
The following report came from intel-gfx ci's
igt@debugfs_test@read_all_entries testcase:
=============================
[ BUG: Invalid wait context ]
5.13.0-CI-Patchwork_20515+ #1 Tainted: G W
-----------------------------
debugfs_test/1101 is trying to lock:
ffff888132d901a8 (&dev->master_mutex){+.+.}-{3:3}, at:
drm_is_current_master+0x1e/0x50
other info that might help us debug this:
context-{4:4}
3 locks held by debugfs_test/1101:
#0: ffff88810fdffc90 (&p->lock){+.+.}-{3:3}, at:
seq_read_iter+0x53/0x3b0
#1: ffff888132d90240 (&dev->filelist_mutex){+.+.}-{3:3}, at:
drm_clients_info+0x63/0x2a0
#2: ffffffff82734220 (rcu_read_lock){....}-{1:2}, at:
drm_clients_info+0x1b1/0x2a0
stack backtrace:
CPU: 8 PID: 1101 Comm: debugfs_test Tainted: G W
5.13.0-CI-Patchwork_20515+ #1
Hardware name: Intel Corporation CometLake Client Platform/CometLake S
UDIMM (ERB/CRB), BIOS CMLSFWR1.R00.1263.D00.1906260926 06/26/2019
Call Trace:
dump_stack+0x7f/0xad
__lock_acquire.cold.78+0x2af/0x2ca
lock_acquire+0xd3/0x300
? drm_is_current_master+0x1e/0x50
? __mutex_lock+0x76/0x970
? lockdep_hardirqs_on+0xbf/0x130
__mutex_lock+0xab/0x970
? drm_is_current_master+0x1e/0x50
? drm_is_current_master+0x1e/0x50
? drm_is_current_master+0x1e/0x50
drm_is_current_master+0x1e/0x50
drm_clients_info+0x107/0x2a0
seq_read_iter+0x178/0x3b0
seq_read+0x104/0x150
full_proxy_read+0x4e/0x80
vfs_read+0xa5/0x1b0
ksys_read+0x5a/0xd0
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210712043508.11584-3-desmondcheongzx@gmail.com
In preparation for a future patch to take a lock on
drm_device.master_mutex inside drm_is_current_master(), we first move
the call to drm_is_current_master() in drm_mode_getconnector out from the
section locked by &dev->mode_config.mutex. This avoids creating a
circular lock dependency.
Failing to avoid this lock dependency produces the following lockdep
splat:
======================================================
WARNING: possible circular locking dependency detected
5.13.0-rc7-CI-CI_DRM_10254+ #1 Not tainted
------------------------------------------------------
kms_frontbuffer/1087 is trying to acquire lock:
ffff88810dcd01a8 (&dev->master_mutex){+.+.}-{3:3}, at: drm_is_current_master+0x1b/0x40
but task is already holding lock:
ffff88810dcd0488 (&dev->mode_config.mutex){+.+.}-{3:3}, at: drm_mode_getconnector+0x1c6/0x4a0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&dev->mode_config.mutex){+.+.}-{3:3}:
__mutex_lock+0xab/0x970
drm_client_modeset_probe+0x22e/0xca0
__drm_fb_helper_initial_config_and_unlock+0x42/0x540
intel_fbdev_initial_config+0xf/0x20 [i915]
async_run_entry_fn+0x28/0x130
process_one_work+0x26d/0x5c0
worker_thread+0x37/0x380
kthread+0x144/0x170
ret_from_fork+0x1f/0x30
-> #1 (&client->modeset_mutex){+.+.}-{3:3}:
__mutex_lock+0xab/0x970
drm_client_modeset_commit_locked+0x1c/0x180
drm_client_modeset_commit+0x1c/0x40
__drm_fb_helper_restore_fbdev_mode_unlocked+0x88/0xb0
drm_fb_helper_set_par+0x34/0x40
intel_fbdev_set_par+0x11/0x40 [i915]
fbcon_init+0x270/0x4f0
visual_init+0xc6/0x130
do_bind_con_driver+0x1e5/0x2d0
do_take_over_console+0x10e/0x180
do_fbcon_takeover+0x53/0xb0
register_framebuffer+0x22d/0x310
__drm_fb_helper_initial_config_and_unlock+0x36c/0x540
intel_fbdev_initial_config+0xf/0x20 [i915]
async_run_entry_fn+0x28/0x130
process_one_work+0x26d/0x5c0
worker_thread+0x37/0x380
kthread+0x144/0x170
ret_from_fork+0x1f/0x30
-> #0 (&dev->master_mutex){+.+.}-{3:3}:
__lock_acquire+0x151e/0x2590
lock_acquire+0xd1/0x3d0
__mutex_lock+0xab/0x970
drm_is_current_master+0x1b/0x40
drm_mode_getconnector+0x37e/0x4a0
drm_ioctl_kernel+0xa8/0xf0
drm_ioctl+0x1e8/0x390
__x64_sys_ioctl+0x6a/0xa0
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
other info that might help us debug this:
Chain exists of: &dev->master_mutex --> &client->modeset_mutex --> &dev->mode_config.mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&dev->mode_config.mutex);
lock(&client->modeset_mutex);
lock(&dev->mode_config.mutex);
lock(&dev->master_mutex);
*** DEADLOCK ***
1 lock held by kms_frontbuffer/1087:
#0: ffff88810dcd0488 (&dev->mode_config.mutex){+.+.}-{3:3}, at: drm_mode_getconnector+0x1c6/0x4a0
stack backtrace:
CPU: 7 PID: 1087 Comm: kms_frontbuffer Not tainted 5.13.0-rc7-CI-CI_DRM_10254+ #1
Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3234.A01.1906141750 06/14/2019
Call Trace:
dump_stack+0x7f/0xad
check_noncircular+0x12e/0x150
__lock_acquire+0x151e/0x2590
lock_acquire+0xd1/0x3d0
__mutex_lock+0xab/0x970
drm_is_current_master+0x1b/0x40
drm_mode_getconnector+0x37e/0x4a0
drm_ioctl_kernel+0xa8/0xf0
drm_ioctl+0x1e8/0x390
__x64_sys_ioctl+0x6a/0xa0
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210712043508.11584-2-desmondcheongzx@gmail.com
[Bug][AST2500]
V1:
When AST2500 acts as stand-alone VGA so that DRAM and DVO initialization
have to be achieved by VGA driver with P2A (PCI to AHB) enabling.
However, HW suggests disable Fast reset mode after DRAM initializaton,
because fast reset mode is mainly designed for ARM ICE debugger.
Once Fast reset is checked as enabling, WDT (Watch Dog Timer) should be
first enabled to avoid system deadlock before disable fast reset mode.
V2:
Use to_pci_dev() to get revision of PCI configuration.
V3:
If SCU00 is not unlocked, just enter its password again.
It is unnecessary to clear AHB lock condition and restore WDT default
setting again, before Fast-reset clearing.
V4:
repatch after "error : could not build fake ancestor" resolved.
V5:
Since CVE_2019_6260 item3, Most of AST2500 have disabled P2A(PCIe to AMBA).
However, for backward compatibility, some patches about P2A, such as items
of v5.2 and v5.3, are considered to be upstreamed with comments.
1. Add define macro to improve source readability.
ast_drv.h, ast_main.c, ast_post.c
2. Add comment about "Fast restet" is enabled for ARM-ICE debugger
ast_post.c
3. Add comment about Reset USB port to patch USB unknown device issue
ast_post.c
Signed-off-by: KuoHsiang Chou <kuohsiang_chou@aspeedtech.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210709080900.4056-1-kuohsiang_chou@aspeedtech.com
The DMA-BUF attachment statistics form a subset of the DMA-BUF
sysfs statistics that recently merged to the drm-misc tree. They are not
UABI yet since they have not merged to the upstream Linux kernel.
Since there has been a reported a performance regression due to the
overhead of sysfs directory creation/teardown during
dma_buf_attach()/dma_buf_detach(), this patch deletes the DMA-BUF
attachment statistics from sysfs.
Fixes: bdb8d06dfe ("dmabuf: Add the capability to expose DMA-BUF stats in sysfs")
Signed-off-by: Hridya Valsaraju <hridya@google.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210713040742.2680135-1-hridya@google.com
Signed-off-by: Christian König <christian.koenig@amd.com>
The user can pass in any value to the driver through the 'ioctl'
interface. The driver dost not check, which may cause DoS bugs.
The following log reveals it:
divide error: 0000 [#1] PREEMPT SMP KASAN PTI
RIP: 0010:SetOverlayViewPort+0x133/0x5f0 drivers/video/fbdev/kyro/STG4000OverlayDevice.c:476
Call Trace:
kyro_dev_overlay_viewport_set drivers/video/fbdev/kyro/fbdev.c:378 [inline]
kyrofb_ioctl+0x2eb/0x330 drivers/video/fbdev/kyro/fbdev.c:603
do_fb_ioctl+0x1f3/0x700 drivers/video/fbdev/core/fbmem.c:1171
fb_ioctl+0xeb/0x130 drivers/video/fbdev/core/fbmem.c:1185
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__x64_sys_ioctl+0x19b/0x220 fs/ioctl.c:739
do_syscall_64+0x32/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1626235762-2590-1-git-send-email-zheyuma97@gmail.com
As dw-mipi-dsi supported all possible ways to find the DSI
devices. It can take multiple iterations for ltdc to find
all components attached to the DSI bridge.
The current ltdc driver failed to find the endpoint as
it returned -EINVAL for the first iteration itself. This leads
to following error:
[ 3.099289] [drm:ltdc_load] *ERROR* init encoder endpoint 0
So, check the return value and cleanup the encoder only if it's
not -EPROBE_DEFER. This make all components in the attached DSI
bridge found properly.
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Yannick Fertre <yannick.fertre@foss.st.com>
Acked-by: Philippe Cornu <philippe.cornu@foss.st.com>
Signed-off-by: Philippe Cornu <philippe.cornu@foss.st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210704135914.268308-1-jagan@amarulasolutions.com
This adds a driver for panels based on the WideChips WS2401 display
controller. This display controller is used in the Samsung LMS380KF01
display found in the Samsung GT-I8160 (Codina) mobile phone and
possibly others.
As is common with Samsung displays manufacturer commands are necessary
to configure the display to a working state.
The display optionally supports internal backlight control, but can
also use an external backlight.
This driver re-uses the DBI infrastructure to communicate with the
display.
Cc: phone-devel@vger.kernel.org
Cc: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210714225002.1065107-2-linus.walleij@linaro.org
Even after the DP AUX backlight on my board worked OK after applying
the patch ("drm/panel-simple: Power the panel when probing DP AUX
backlight") [1], I still noticed some strange timeouts being reported
by ti_sn_aux_transfer(). Digging, I realized the problem was this:
* Even though `enabled` in `struct dp_aux_backlight` was false, the
base backlight structure (`base` in that structure) thought that the
backlight was powered on.
* If userspace wrote to sysfs in this state then we'd try to enable
the backlight.
* Unfortunatley, enabling the backlight didn't work because the panel
itself wasn't powered.
We can only use the backlight if the panel is on and the panel is not
officially on when we probe (it's temporarily just on enough for us to
talk to it).
The important thing we want here is to get `BL_CORE_FBBLANK` set since
userspace can't mess with that. This will keep us disabled until
drm_panel enables us, which means that the panel is enabled
first. Ideally we'd just set this in our `props` before calling
devm_backlight_device_register() but the comments in the header file
are pretty explicit that we're not supposed to much with the `state`
ourselves. Because of this, there may be a small window where the
backlight device is registered and someone could try to tweak with the
backlight. This isn't likely to happen and even if it did, I don't
believe this causes any huge problem.
[1] https://lore.kernel.org/lkml/20210714093334.1.Idb41f87e5abae4aee0705db7458b0097fc50e7ab@changeid/
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210714101744.1.Ifc22696b27930749915e383f0108b7bcdc015a6e@changeid
When I tried booting up a device that needed the DP AUX backlight, I
found an error in the logs:
panel-simple-dp-aux: probe of aux-ti_sn65dsi86.aux.0 failed with error -110
The aux transfers were failing because the panel wasn't powered. Just
like when reading the EDID we need to power the panel when trying to
talk to it. Add the needed pm_runtime calls.
After I do this I can successfully probe the panel and adjust the
backlight on my board.
Fixes: bfd451403d ("drm/panel-simple: Support DP AUX backlight")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210714093334.1.Idb41f87e5abae4aee0705db7458b0097fc50e7ab@changeid
Our hotplug handler will currently call the drm_kms_helper_hotplug_event
every time a hotplug interrupt is called.
However, since the device is registered after all the drivers have
finished their bind callback, we have a window between when we install
our interrupt handler and when drm_dev_register() is eventually called
where our handler can run and call drm_kms_helper_hotplug_event but the
device hasn't been registered yet, causing a null pointer dereference.
Fix this by making sure we only call drm_kms_helper_hotplug_event if our
device has been properly registered.
Fixes: f4790083c7 ("drm/vc4: hdmi: Rely on interrupts to handle hotplug")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210707095112.1469670-4-maxime@cerno.tech
The hotplugs interrupt handlers are registered through the
devm_request_threaded_irq function. However, while free_irq is indeed
called properly when the device is unbound or bind fails, it's called
after unbind or bind is done.
In our particular case, it means that on failure it creates a window
where our interrupt handler can be called, but we're freeing every
resource (CEC adapter, DRM objects, etc.) it might need.
In order to address this, let's switch to the non-devm variant to
control better when the handler will be unregistered and allow us to
make it safe.
Fixes: f4790083c7 ("drm/vc4: hdmi: Rely on interrupts to handle hotplug")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210707095112.1469670-3-maxime@cerno.tech
We were getting a depmod error:
depmod: ERROR: Cycle detected: drm_kms_helper -> drm -> drm_kms_helper
It looks like the rule is that drm_kms_helper can call into drm, but
drm can't call into drm_kms_helper. That means we've got to move the
DP AUX backlight support into drm_dp_helper.
NOTE: as part of this, I didn't try to do any renames of the main
registration function. Even though it's in the drm_dp_helper, it still
feels very parallel to drm_panel_of_backlight().
Fixes: 10f7b40e4f ("drm/panel: add basic DP AUX backlight support")
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reported-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Rajeev Nandan <rajeevny@codeaurora.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210712075933.v2.1.I23eb4cc5a680341e7b3e791632a635566fa5806a@changeid
Store the shadow-buffer mapping's address in struct vkms_composer and
use the value when composing the output. It's the same value as stored
in the GEM SHMEM BO, but frees the composer code from its dependency
on GEM SHMEM.
Using struct dma_buf_map is how framebuffer access is supposed to be.
The long-term plan is to perform all framebuffer access via struct
dma_buf_map and avoid the details of accessing I/O and system memory.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210705074633.9425-5-tzimmermann@suse.de
Replace vkms' prepare_fb and cleanup_fb functions with the generic
code for shadow-buffered planes. No functional changes.
This change also fixes a problem where IGT kms_flip tests would
create a segmentation fault within vkms. The driver's prepare_fb
function did not report an error if a BO's vmap operation failed.
The kernel later tried to operate on the non-mapped memory areas.
The shared shadow-plane helpers handle errors correctly, so that
the driver now avoids the segmantation fault.
v2:
* include paragraph about IGT tests in commit message (Melissa)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210705074633.9425-4-tzimmermann@suse.de
Some panels support backlight control over DP AUX channel using
VESA's standard backlight control interface.
Using new DRM eDP backlight helpers, add support to create and
register a backlight for those panels in drm_panel to simplify
the panel drivers.
The panel driver with access to "struct drm_dp_aux" can create and
register a backlight device using following code snippet in its
probe() function:
err = drm_panel_dp_aux_backlight(panel, aux);
if (err)
return err;
Then drm_panel will handle backlight_(enable|disable) calls
similar to the case when drm_panel_of_backlight() is used.
Currently, we are not supporting one feature where the source
device can combine the backlight brightness levels set through
DP AUX and the BL_PWM_DIM eDP connector pin. Since it's not
required for the basic backlight controls, it can be added later.
Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Lyude Paul <lyude@redhat.com>
[dianders: added blank line for warning when applying]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1624726268-14869-2-git-send-email-rajeevny@codeaurora.org
