Replace simple-display helpers with regular atomic helpers. Store the
pipeline elements in struct st7586_device and initialize them as part
of probing the device. Use mipi-dbi's existing helpers and initializer
macros where possible.
Effectively open-codes the modesetting code in the initializer helpers
of mipi-dbi and simple-display. St7586 requires custom helpers for
various pipeline elements, and non-freeing cleanup of the pipeline.
v3:
- return early in st7586_plane_helper_atomic_update (David)
v2:
- fix connector initialization
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-12-tzimmermann@suse.de
Replace simple-display helpers with regular atomic helpers. Store the
pipeline elements in struct panel_mipi_dbi_device and initialize them as
part of probing the device. Use mipi-dbi's existing helpers and initializer
macros where possible.
Effectively open-codes the modesetting code in the initializer helpers
of mipi-dbi and simple-display. Panel-mipi-dbi requires a custom helper
for CRTC enablement, and non-freeing cleanup of the pipeline.
v2:
- fix connector initialization
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-11-tzimmermann@suse.de
Replace simple-display helpers with regular atomic helpers. Store the
pipeline elements in struct mi0283qt_device and initialize them as part
of probing the device. Use mipi-dbi's existing helpers and initializer
macros where possible.
Effectively open-codes the modesetting code in the initializer helpers
of mipi-dbi and simple-display. Mi0283qt requires a custom helper for
CRTC enablement, and non-freeing cleanup of the pipeline.
v3:
- set dbi variable (David)
v2:
- fix connector initialization
- fix coding style
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-10-tzimmermann@suse.de
Replace simple-display helpers with regular atomic helpers. Store the
pipeline elements in struct ili9486_device and initialize them as part
of probing the device. Use mipi-dbi's existing helpers and initializer
macros where possible.
Effectively open-codes the modesetting code in the initializer helpers
of mipi-dbi and simple-display. Ili9486 requires a custom helper for
CRTC enablement, and non-freeing cleanup of the pipeline.
v3:
- set ili9486 variable (David)
v2:
- fix connector initialization
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-9-tzimmermann@suse.de
Replace simple-display helpers with regular atomic helpers. Store the
pipeline elements in struct ili9341_device and initialize them as part
of probing the device. Use mipi-dbi's existing helpers and initializer
macros where possible.
Effectively open-codes the modesetting code in the initializer helpers
of mipi-dbi and simple-display. Ili9341 requires a custom helper for
CRTC enablement, and non-freeing cleanup of the pipeline.
v3:
- set dbi variable (David)
v2:
- fix connector initialization
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-8-tzimmermann@suse.de
Replace simple-display helpers with regular atomic helpers. Store the
pipeline elements in struct ili9225_device and initialize them as part
of probing the device. Use mipi-dbi's existing helpers and initializer
macros where possible.
Effectively open-codes the modesetting code in the initializer helpers
of mipi-dbi and simple-display. Ili9225 requires custom helpers for
various pipeline elements, and non-freeing cleanup of the pipeline.
v3:
- set dbi variable (David)
v2:
- fix connector initialization
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-7-tzimmermann@suse.de
Replace simple-display helpers with regular atomic helpers. Store the
pipeline elements in struct ili9163_device and initialize them as part
of probing the device. Use mipi-dbi's existing helpers and initializer
macros where possible.
Effectively open-codes the modesetting code in the initializer helpers
of mipi-dbi and simple-display. Ili9163 requires a custom helper for
CRTC enablement, and non-freeing cleanup of the pipeline.
v3:
- set dbi variable (David)
v2:
- fix connector initialization
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-6-tzimmermann@suse.de
Replace simple-display helpers with regular atomic helpers. Store the
pipeline elements in struct hx8357d_device and initialize them as part
of probing the device. Use mipi-dbi's existing helpers and initializer
macros where possible.
Effectively open-codes the modesetting code in the initializer helpers
of mipi-dbi and simple-display. Hx8357d requires a custom helper for
CRTC enablement, and non-freeing cleanup of the pipeline.
v2:
- fix connector initialization
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-5-tzimmermann@suse.de
Refactor the existing simple-display callbacks such that they invoke
helpers compatible with regular atomic modesetting. Allows for adding
mipi-dbi drives that do not require simple-display helpers.
Provide initializer macro for elements of the regular modesetting
pipeline. These will be used by drivers to integrate mipi-dbi helpers.
Also provide initializer macros for the plane formats.
As the new helpers are DRM functions, add the drm_ prefix. Mipi-dbi
interfaces currently lack this.
v3:
- fix uninitialized variable (David)
- document public interfaces (David)
- mention format macros in commit message (David)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-4-tzimmermann@suse.de
Use drm_atomic_helper_commit_tail_rpm() as commit tail to update the
plane after enabling the CRTC. Then remove the plane-update code from
mipi_dbi_enable_flush() and inline the remaining backlight code where
necessary.
Mipi-dbi's current commit tail drm_atomic_helper_commit_tail() first
updates the plane and then enables the CRTC. But the CRTC enablement
includes power management that prevents the initial plane update from
working. Hence, each mipi-dbi driver includes a plane update in their
CRTC enablement; in the form of mipi_dbi_enable_flush() or custom code.
Using drm_atomic_helper_commit_tail_rpm() enables the CRTC before any
plane updates. Hence the additional plane update can be removed from
mipi_dbi_enable_flush() and a number of drivers.
This leaves backlight_enable() in the helper, which can now be inlined
into affected drivers. Drivers now enable the CRTC plus an optional
backlight and then automatically update the plane.
In the case of disabling the display, drm_atomic_helper_commit_tail_rpm()
only disables the CRTC without touching the plane at all. Mipi-dbi's
mipi_dbi_pipe_disable() already contains the necessary logic.
Removing the plane update from the CRTC enablement will also help with
converting mipi-dbi from simple-pipe helpers to regular atomic helpers.
v3:
- st7586: remove unused variable
v2:
- ili9225: remove unused variables (David)
- st7586: remove unused variables (David)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-2-tzimmermann@suse.de
On 32-bit kernels, 64-bit integers cannot be passed to the division operator:
ld.lld-22: error: undefined symbol: __aeabi_uldivmod
>>> referenced by lontium-lt8713sx.c
>>> drivers/gpu/drm/bridge/lontium-lt8713sx.o:(lt8713sx_firmware_store) in archive vmlinux.a
Since this is a constant number used to divide a size_t, just change the type
to that as well.
Fixes: 4037c6adc1 ("drm/bridge: add support for lontium lt8713sx bridge driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260316215920.1993390-1-arnd@kernel.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Arm China Linlon-D6 is register-compatible with the Mali-D71 display
pipeline for the purpose of basic modesetting.
On Linlon-D6, the PRODUCT_ID register is located at the same offset as on
Mali-D71 and reports 0x0060. The IP also exposes the same Komeda top-level
block layout expected by the existing d71_identify() probing flow, so we
can reuse the D71 function table to bring up the display engine.
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Cunyuan Liu <cunyuan.liu@cixtech.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patch.msgid.link/20260313033119.33686-4-cunyuan.liu@cixtech.com
The DRM_TTM_KUNIT_TEST config option should default
to KUNIT_ALL_TESTS so that if all tests are enabled then
it is included, but currently the 'default KUNIT_ALL_TESTS'
statement is shadowed by an unconditional 'default n',
meaning that this second default statement is currently dead code.
This dead code was found by kconfirm, a static analysis
tool for Kconfig.
Signed-off-by: Julian Braha <julianbraha@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20260323124118.1414913-1-julianbraha@gmail.com
The hdmi_colorspace enum was defined to represent the colorspace value
of the HDMI infoframes. It was later used by some HDMI drivers to
express the output format they should be setting up.
During the introduction of the HDMI helpers, it then was used to
represent it in the drm_connector_hdmi_state structure.
However, it's always been somewhat redundant with the DRM_COLOR_FORMAT_*
defines, and now with the drm_output_color_format enum. Let's
consolidate around drm_output_color_format in drm_connector_hdmi_state
to facilitate the current effort to provide a global output format
selection mechanism.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-14-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-12-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-11-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-10-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-9-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-8-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-7-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-6-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-5-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-4-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-3-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Now that we introduced a new drm_output_color_format enum to represent
what DRM_COLOR_FORMAT_* bits were representing, we can switch to the new
enum.
The main difference is that while DRM_COLOR_FORMAT_ was a bitmask,
drm_output_color_format is a proper enum. However, the enum was done is
such a way than DRM_COLOR_FORMAT_X = BIT(DRM_OUTPUT_COLOR_FORMAT_X) so
the transitition is easier.
The only thing we need to consider is if the original code meant to use
that value as a bitmask, in which case we do need to keep the bit shift,
or as a discriminant in which case we don't.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260305-drm-rework-color-formats-v3-2-f3935f6db579@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
The sun4i DRM driver deals with DMA constraints in a peculiar way.
Instead of using the actual DMA device in various helpers, it justs
reconfigures the DMA constraints of the virtual display device using
the DMA device's device tree node by calling of_dma_configure().
Turns out of_dma_configure() should only be called from bus code.
Lately this also triggers a big warning through of_iommu_configure()
and ultimately __iommu_probe_device():
late IOMMU probe at driver bind, something fishy here!
Now that the GEM DMA helpers have proper support for allocating
and mapping buffers with a dedicated DMA device, switch over to
it as the proper solution.
The mixer change was tested on a Pine H64 model B. The backend change
was only compile tested. Though I don't expect any issues, help testing
on an older device would be appreciated.
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://patch.msgid.link/20260311094929.3393338-5-wenst@chromium.org
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
In commit 9b54a32c7c ("drm/mediatek: mtk_gem: Partial refactor and
use drm_gem_dma_object") the MediaTek DRM driver was refactored to use
drm_gem_dma_object, but custom callbacks were still needed to deal with
using the first device of the pipeline as the DMA device, instead of
the MMSYS device that the DRM driver binds to.
Turns out there is already partial support for dedicated DMA devices in
the DRM subsystem for PRIME imports. The preceding patches add support
for dedicated DMA devices to the GEM DMA helpers.
This allows us to just set the dedicated DMA device for the DRM device,
and drop all the custom GEM callbacks. Also drop the .dma_dev field
from the driver private data as it is no longer needed.
There are slight differences in the mmap helper: the VM_DONTDUMP and
VM_IO flags are no longer set. Both were lifted from drm_gem_mmap_obj().
VM_IO probably doesn't make sense since the buffer is allocated using
dma_alloc_attrs().
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20260311094929.3393338-4-wenst@chromium.org
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Support for a dedicated DMA device for prime imports was added in commit
143ec8d3f9 ("drm/prime: Support dedicated DMA device for dma-buf imports").
This allowed the DRM driver to provide a dedicated DMA device when its
own underlying device was not capable of DMA, for example when it is a
USB device (the original target) or a virtual device. The latter case is
common on embedded SoCs, on which the display pipeline is composed of
various fixed function blocks, and the DRM device is simply a made-up
device, an address space managing the routing between the blocks, or
whichever block the implementor thought made sense at the time. The
point is that the chosen device is often not the actual device doing
the DMA. Various drivers have used workarounds or reimplemented the
GEM DMA helpers to get the DMA addresses and IOMMUs to work correctly.
Add support for the dedicated DMA device to the GEM DMA helpers.
No existing driver currently uses the GEM DMA helpers and calls
drm_dev_set_dma_dev() to set a dedicated DMA device, so no existing
users should be affected.
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20260311094929.3393338-3-wenst@chromium.org
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
If a dedicated DMA device is specified for the DRM device, then the
scatter list size limit should pertain to the DMA device.
Use the dedicated DMA device, if given, to limit the scatter list size.
This only applies to drivers that have called drm_dev_set_dma_dev() and
are using drm_prime_pages_to_sg() either directly or through the SHMEM
helpers. At the time of this writing, the former case only includes the
Rockchip DRM driver, while the latter case includes the gud, udl, and
the tiny appletbdrm and gm12u320 drivers.
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20260311094929.3393338-2-wenst@chromium.org
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Drivers having a struct drm_bridge pointer pointing to a bridge in many
cases hold that reference until the owning device is removed. In those
cases the reference to the bridge can be put in the .remove callback
(possibly using devm actions) or in the .destroy func (possibly with the
help of struct drm_bridge::next_bridge). At those moments the driver should
not be operating anymore and won't dereference the bridge pointer after it
is put.
However there are cases when drivers need to stop holding a reference to a
bridge even when their device is not being removed. This is the case for
bridge hot-unplug, when a bridge is removed but the previous entity (bridge
or encoder) is staying. In such case the "previous entity" needs to put it
but cannot do it via devm or .destroy, because it is not being removed.
The easy way to dispose of such pointer is:
drm_bridge_put(my_priv->some_bridge);
my_priv->some_bridge = NULL;
However this is risky because there is a time window between the two lines
where the reference is put, and thus the bridge could be deallocated, but
the pointer is still assigned. If other functions of the same driver were
invoked concurrently they might dereference my_priv->some_bridge during
that window, resulting in use-after-free.
A correct solution is to clear the pointer before putting the reference,
but that needs a temporary variable:
struct drm_bridge *temp = my_priv->some_bridge;
my_priv->some_bridge = NULL;
drm_bridge_put(temp);
This solution is however annoying to write, so the incorrect version might
still sneak in.
Add a simple, easy to use function to put a bridge after setting its
pointer to NULL in the correct way.
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://patch.msgid.link/20260310-drm-bridge-atomic-vs-remove-clear_and_put-v2-1-51fe222f3cf0@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
