The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200221160005.GA13552@embeddedor
This patch makes the internal encoder implementation of the simple
KMS helpers available to drivers.
These simple-encoder helpers initialize an encoder with an empty
implementation. This covers the requirements of most of the existing
DRM drivers. A call to drm_simple_encoder_create() allocates and
initializes an encoder instance, a call to drm_simple_encoder_init()
initializes a pre-allocated instance.
v3:
* remove drm_simple_encoder_create(); not required yet
* provide more precise documentation
v2:
* move simple encoder to KMS helpers
* remove name argument; simplifies implementation
* don't allocate with devm_ interfaces; unsafe with DRM
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228081828.18463-2-tzimmermann@suse.de
The panel-dpi compatible is a fallback that
allows the DT to specify the timing.
When matching panel-dpi expect the device tree to include the
timing information for the display-panel.
Background for this change:
There are a lot of panels and new models hits the market very often.
It is a lost cause trying to chase them all and users of new panels
will often find them in situations that the panel they ues are not
supported by the kernel.
On top of this a lot of panels are customized based on customer
specifications.
Including the panel timing in the device tree allows for a simple
way to describe the actual HW and use this description in a generic
way in the kernel.
This allows uses of proprietary panels, or panels which are not
included in the kernel, to specify the timing in the device tree
together with all the other HW descriptions.
And thus, using the device tree it is then easy to add support
for an otherwise unknown panel.
The current support expect panels that do not require any
delays for prepare/enable/disable/unprepare.
Oleksandr Suvorov replied:
I've just tested this patch on Apalis iMX6Q and Colibri iMX7D using
panel settings from the following patch:
https://lore.kernel.org/linux-arm-kernel/20200115123401.2264293-4-oleksandr.suvorov@toradex.com/
It works for me, thanks!
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Tested-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200216181513.28109-6-sam@ravnborg.org
With panel-timing converted, now convert the single
remaining .txt user in panel/ of panel-timing to DT schema.
v2:
- Drop Thierry as maintainer, as this is not a general panel binding
and I have no acks.
- Drop requirement for a panel- specific binding - "panel-dpi" is enough
- Updated example
v3:
- added yaml document terminator "..."
- always require a specific binding - panel-dpi (based on feedback from Rob)
- use "power-supply" for the supply property, and made it mandatory
"power-supply" is the standard property for panels
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200216181513.28109-4-sam@ravnborg.org
Add meta-schema variant of panel-timing and
reference it from panel-common.yaml.
Part of this came form other files with other
licenses - original commits:
commit cc3f414cf2 ("video: add of helper for display timings/videomode")
commit 86f46565df ("dt-bindings: display: display-timing: Add property to configure sync drive edge")
commit 9cad9c95d7 ("Documentation: DocBook DRM framework documentation")
The original authors acked the license change to:
(GPL-2.0-only OR BSD-2-Clause)
v2:
- Got OK from original authors for re-license
Huge thanks for the quick replies!
- Typo fixes (Oleksandr)
- Drop -array variant when not needed (Maxime)
- Replace oneOf:... with enum (Maxime)
- Drop type from clock-frequency (Rob)
- Drop "|" when not needed (Rob)
v3:
- Added comment to acks that are only for the license change
- Add yaml document terminator "..."
- Updated description (removed reference to native-mode)
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> [license change]
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com> [license change]
Acked-by: Steffen Trumtrar <s.trumtrar@pengutronix.de> [license change]
Acked-by: Philipp Zabel <p.zabel@pengutronix.de> [license change]
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: devicetree@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200216181513.28109-2-sam@ravnborg.org
The old implementation of placing planes on the CRTC while configuring
the planes was naive and relied on the order in which the planes were
configured, enabled, and disabled. The situation where a plane's zpos
was changed on the fly was completely broken. The usual symptoms of
this problem was scrambled display and a flood of sync lost errors,
when a plane was active in two layers at the same time, or a missing
plane, in case when a layer was accidentally disabled.
The rewrite takes a more straight forward approach when HW is
concerned. The plane positioning registers are in the CRTC (or
actually OVR) register space and it is more natural to configure them
in a one go when configuring the CRTC. To do this we need make sure we
have all the planes on the updated CRTCs in the new atomic state. The
untouched planes on CRTCs that need plane position update are added to
the atomic state in tidss_atomic_check().
Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200227120052.23168-1-jsarha@ti.com
On the exporter side we add optional explicit pinning callbacks. Which are
called when the importer doesn't implement dynamic handling, move notification
or need the DMA-buf locked in place for its use case.
On the importer side we add an optional move_notify callback. This callback is
used by the exporter to inform the importers that their mappings should be
destroyed as soon as possible.
This allows the exporter to provide the mappings without the need to pin
the backing store.
v2: don't try to invalidate mappings when the callback is NULL,
lock the reservation obj while using the attachments,
add helper to set the callback
v3: move flag for invalidation support into the DMA-buf,
use new attach_info structure to set the callback
v4: use importer_priv field instead of mangling exporter priv.
v5: drop invalidation_supported flag
v6: squash together with pin/unpin changes
v7: pin/unpin takes an attachment now
v8: nuke dma_buf_attachment_(map|unmap)_locked,
everything is now handled backward compatible
v9: always cache when export/importer don't agree on dynamic handling
v10: minimal style cleanup
v11: drop automatically re-entry avoidance
v12: rename callback to move_notify
v13: add might_lock in appropriate places
v14: rebase on separated locking change
v15: add EXPERIMENTAL flag, some more code comments
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/353993/?series=73646&rev=1
