[PATCH] drm/vkms: add module parameter to set background color
Maíra Canal
mcanal at igalia.com
Thu Apr 6 18:06:56 UTC 2023
On 4/6/23 14:28, Daniel Vetter wrote:
> On Thu, 6 Apr 2023 at 19:20, Maíra Canal <mcanal at igalia.com> wrote:
>>
>> After commit 8ba1648567e2 ("drm: vkms: Refactor the plane composer to
>> accept new formats") the composition is no longer performed on top of
>> the primary plane, but instead on top of the CRTC, which means that
>> now we have a background.
>>
>> This opens to the possibility of coloring the background with a
>> personalized color. Therefore, create a module parameter that takes a
>> unsigned long number as an XRGB16161616 color and set the background
>> color to it. That said, the composition will be performed on top of
>> this background color. By default, the background color is black.
>>
>> Signed-off-by: Maíra Canal <mcanal at igalia.com>
>> ---
>>
>> This patch intends to add a background color property to vkms through
>> a module parameter. Another option would be to implement this property
>> by adding a new KMS property that would indicate the background color.
>> It would be nice to hear other opinions on what would be the best
>> approach.
>
> These patches (and I think even igts for them) have been floating
> around for years. The hang-up is the userspace. Turns out all
> compositors want for background is black, thus far no one has figured
> out a real use-case for anything else.
>
> Maybe some time ...
>
But, would it be okay to add this feature as a vkms' module parameter?
>> Moreover, I wrote some IGT tests to ensure that the functionality is
>> working correctly [1]. The tests take the CRC of a colored primary
>> plane, offset the primary plane out of the screen, and take the CRC
>> of the colored background. The two CRC must be equal.
>>
>> [1] https://gitlab.freedesktop.org/mairacanal/igt-gpu-tools/-/tree/vkms/background-color
>
> I wonder whether it would be more useful to have this as a Kunit
> validation test to very that the vkms composing code works correctly?
> Still with the modparam and vkms_config to handle it all cleanly.
Not sure if this would fit as a unit test, as the vkms composing
code basically outputs a CRC, which can be better verified by
the userspace. The output_buffer and stage_buffer are internal
variables, so it would be difficult to evaluate them with a KUnit
test.
With the IGT test, we can assure that the background composition
is being performed properly using the CRC in a negative test and
also some positive tests.
Best Regards,
- Maíra Canal
> -Daniel
>
>>
>> Best Regards,
>> - Maíra Canal
>>
>> ---
>> Documentation/gpu/vkms.rst | 2 --
>> drivers/gpu/drm/vkms/vkms_composer.c | 20 ++++++++++++++------
>> drivers/gpu/drm/vkms/vkms_drv.c | 6 ++++++
>> drivers/gpu/drm/vkms/vkms_drv.h | 4 ++++
>> 4 files changed, 24 insertions(+), 8 deletions(-)
>>
>> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
>> index 49db221c0f52..dc01689d8c76 100644
>> --- a/Documentation/gpu/vkms.rst
>> +++ b/Documentation/gpu/vkms.rst
>> @@ -121,8 +121,6 @@ There's lots of plane features we could add support for:
>> - ARGB format on primary plane: blend the primary plane into background with
>> translucent alpha.
>>
>> -- Add background color KMS property[Good to get started].
>> -
>> - Full alpha blending on all planes.
>>
>> - Rotation, scaling.
>> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
>> index 8e53fa80742b..07345faee98a 100644
>> --- a/drivers/gpu/drm/vkms/vkms_composer.c
>> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
>> @@ -79,7 +79,8 @@ static void fill_background(const struct pixel_argb_u16 *background_color,
>> * from all planes, calculates the crc32 of the output from the former step,
>> * and, if necessary, convert and store the output to the writeback buffer.
>> */
>> -static void blend(struct vkms_writeback_job *wb,
>> +static void blend(struct vkms_device *vkms_dev,
>> + struct vkms_writeback_job *wb,
>> struct vkms_crtc_state *crtc_state,
>> u32 *crc32, struct line_buffer *stage_buffer,
>> struct line_buffer *output_buffer, size_t row_size)
>> @@ -87,7 +88,12 @@ static void blend(struct vkms_writeback_job *wb,
>> struct vkms_plane_state **plane = crtc_state->active_planes;
>> u32 n_active_planes = crtc_state->num_active_planes;
>>
>> - const struct pixel_argb_u16 background_color = { .a = 0xffff };
>> + const struct pixel_argb_u16 background_color = {
>> + .a = 0xffff,
>> + .r = (*vkms_dev->config->background_color >> 32) & 0xffff,
>> + .g = (*vkms_dev->config->background_color >> 16) & 0xffff,
>> + .b = *vkms_dev->config->background_color & 0xffff,
>> + };
>>
>> size_t crtc_y_limit = crtc_state->base.crtc->mode.vdisplay;
>>
>> @@ -139,7 +145,8 @@ static int check_iosys_map(struct vkms_crtc_state *crtc_state)
>> return 0;
>> }
>>
>> -static int compose_active_planes(struct vkms_writeback_job *active_wb,
>> +static int compose_active_planes(struct vkms_device *vkms_dev,
>> + struct vkms_writeback_job *active_wb,
>> struct vkms_crtc_state *crtc_state,
>> u32 *crc32)
>> {
>> @@ -178,7 +185,7 @@ static int compose_active_planes(struct vkms_writeback_job *active_wb,
>> goto free_stage_buffer;
>> }
>>
>> - blend(active_wb, crtc_state, crc32, &stage_buffer,
>> + blend(vkms_dev, active_wb, crtc_state, crc32, &stage_buffer,
>> &output_buffer, line_width * pixel_size);
>>
>> kvfree(output_buffer.pixels);
>> @@ -205,6 +212,7 @@ void vkms_composer_worker(struct work_struct *work)
>> struct drm_crtc *crtc = crtc_state->base.crtc;
>> struct vkms_writeback_job *active_wb = crtc_state->active_writeback;
>> struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
>> + struct vkms_device *vkms_dev = vkms_output_to_vkms_device(out);
>> bool crc_pending, wb_pending;
>> u64 frame_start, frame_end;
>> u32 crc32 = 0;
>> @@ -228,9 +236,9 @@ void vkms_composer_worker(struct work_struct *work)
>> return;
>>
>> if (wb_pending)
>> - ret = compose_active_planes(active_wb, crtc_state, &crc32);
>> + ret = compose_active_planes(vkms_dev, active_wb, crtc_state, &crc32);
>> else
>> - ret = compose_active_planes(NULL, crtc_state, &crc32);
>> + ret = compose_active_planes(vkms_dev, NULL, crtc_state, &crc32);
>>
>> if (ret)
>> return;
>> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
>> index 6d3a2d57d992..a4938dcb8c3e 100644
>> --- a/drivers/gpu/drm/vkms/vkms_drv.c
>> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
>> @@ -51,6 +51,10 @@ static bool enable_overlay;
>> module_param_named(enable_overlay, enable_overlay, bool, 0444);
>> MODULE_PARM_DESC(enable_overlay, "Enable/Disable overlay support");
>>
>> +static unsigned long background_color = 0x000000000000;
>> +module_param_named(background_color, background_color, ulong, 0644);
>> +MODULE_PARM_DESC(background_color, "Background color (0xRRRRGGGGBBBB)");
>> +
>> DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
>>
>> static void vkms_release(struct drm_device *dev)
>> @@ -99,6 +103,7 @@ static int vkms_config_show(struct seq_file *m, void *data)
>> seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
>> seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
>> seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
>> + seq_printf(m, "background_color=0x%lx\n", *vkmsdev->config->background_color);
>>
>> return 0;
>> }
>> @@ -226,6 +231,7 @@ static int __init vkms_init(void)
>> config->cursor = enable_cursor;
>> config->writeback = enable_writeback;
>> config->overlay = enable_overlay;
>> + config->background_color = &background_color;
>>
>> ret = vkms_create(config);
>> if (ret)
>> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
>> index 4a248567efb2..4bc2e6a6d219 100644
>> --- a/drivers/gpu/drm/vkms/vkms_drv.h
>> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
>> @@ -113,6 +113,7 @@ struct vkms_config {
>> bool writeback;
>> bool cursor;
>> bool overlay;
>> + unsigned long *background_color;
>> /* only set when instantiated */
>> struct vkms_device *dev;
>> };
>> @@ -127,6 +128,9 @@ struct vkms_device {
>> #define drm_crtc_to_vkms_output(target) \
>> container_of(target, struct vkms_output, crtc)
>>
>> +#define vkms_output_to_vkms_device(target) \
>> + container_of(target, struct vkms_device, output)
>> +
>> #define drm_device_to_vkms_device(target) \
>> container_of(target, struct vkms_device, drm)
>>
>> --
>> 2.39.2
>>
>
>
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