Hi Werner,
mið., 10. jan. 2024 kl. 13:14 skrifaði Werner Sembach
<w...@tuxedocomputers.com>:
>
> Hi,
>
> Am 10.01.24 um 14:09 schrieb Daniel Vetter:
> > On Wed, 10 Jan 2024 at 13:53, Andri Yngvason <an...@yngvason.is> wrote:
> >> mið., 10. jan. 2024 kl. 11:10 skrifaði Daniel Vetter <dan...@ffwll.ch>:
> >>> On Tue, Jan 09, 2024 at 06:11:00PM +0000, Andri Yngvason wrote:
> >>>> + /* Extract information from crtc to communicate it to userspace as
> >>>> connector properties */
> >>>> + for_each_new_connector_in_state(state, connector, new_con_state,
> >>>> i) {
> >>>> + struct drm_crtc *crtc = new_con_state->crtc;
> >>>> + struct dc_stream_state *stream;
> >>>> +
> >>>> + if (crtc) {
> >>>> + new_crtc_state =
> >>>> drm_atomic_get_new_crtc_state(state, crtc);
> >>>> + dm_new_crtc_state =
> >>>> to_dm_crtc_state(new_crtc_state);
> >>>> + stream = dm_new_crtc_state->stream;
> >>>> +
> >>>> + if (stream) {
> >>>> +
> >>>> drm_connector_set_active_color_format_property(connector,
> >>>> +
> >>>> convert_dc_pixel_encoding_into_drm_color_format(
> >>>> +
> >>>> dm_new_crtc_state->stream->timing.pixel_encoding));
> >>>> + }
> >>>> + } else {
> >>>> +
> >>>> drm_connector_set_active_color_format_property(connector, 0);
> >>> Just realized an even bigger reason why your current design doesn't work:
> >>> You don't have locking here.
> >>>
> >>> And you cannot grab the required lock, which is
> >>> drm_dev->mode_config.mutex, because that would result in deadlocks. So
> >>> this really needs to use the atomic state based design I've described.
> >>>
> >> Maybe we should just drop "actual color format" and instead fail the
> >> modeset if the "preferred color format" property cannot be satisfied?
> >> It seems like the simplest thing to do here, though it is perhaps less
> >> convenient for userspace. In that case, the "preferred color format"
> >> property should just be called "color format".
> > Yeah that's more in line with how other atomic properties work. This
> > way userspace can figure out what works with a TEST_ONLY commit too.
> > And for this to work you probably want to have an "automatic" setting
> > too.
> > -Sima
>
> The problem with TEST_ONLY probing is that color format settings are
> interdependent:
> https://gitlab.freedesktop.org/drm/amd/-/issues/476#note_966634
>
> So changing any other setting may require every color format to be TEST_ONLY
> probed again.
>
If we put a bit map containing the possible color formats into
drm_mode_mode_info (I'm thinking that it could go into flags), we'd be
able to eliminate a bunch of combinations early on. Do you think that
would make things more bearable?
I'm thinking, something like this:
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 128d09138ceb3..59980803cb89e 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -124,6 +124,13 @@ extern "C" {
#define DRM_MODE_FLAG_PIC_AR_256_135 \
(DRM_MODE_PICTURE_ASPECT_256_135<<19)
+/* Possible color formats (4 bits) */
+#define DRM_MODE_FLAG_COLOR_FORMAT_MASK (0x0f << 22)
+#define DRM_MODE_FLAG_COLOR_FORMAT_RGB (1 << 22)
+#define DRM_MODE_FLAG_COLOR_FORMAT_YCBCR444 (1 << 23)
+#define DRM_MODE_FLAG_COLOR_FORMAT_YCBCR422 (1 << 24)
+#define DRM_MODE_FLAG_COLOR_FORMAT_YCBCR420 (1 << 25)
+
#define DRM_MODE_FLAG_ALL (DRM_MODE_FLAG_PHSYNC | \
DRM_MODE_FLAG_NHSYNC | \
DRM_MODE_FLAG_PVSYNC | \
@@ -136,7 +143,8 @@ extern "C" {
DRM_MODE_FLAG_HSKEW | \
DRM_MODE_FLAG_DBLCLK | \
DRM_MODE_FLAG_CLKDIV2 | \
- DRM_MODE_FLAG_3D_MASK)
+ DRM_MODE_FLAG_3D_MASK | \
+ DRM_MODE_FLAG_COLOR_FORMAT_MASK)
/* DPMS flags */
/* bit compatible with the xorg definitions. */
