[PATCH] drm/vkms: add module parameter to set background color
Daniel Vetter
daniel at ffwll.ch
Thu Apr 6 18:23:10 UTC 2023
On Thu, Apr 06, 2023 at 03:06:56PM -0300, Maíra Canal wrote:
> 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?
Yeah I think that's ok.
> > > 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.
I was just thinking of how you could keep the test, because igt is for
uapi in general. So doesn't fit all that well, validating internals is
more what kunit is supposed to do.
-Daniel
>
> 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
> > >
> >
> >
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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