Re: [PATCH 18/18] drm/vc4: hdmi: Force YUV422 if the rate is too high

Am 17.03.21 um 16:43 schrieb Maxime Ripard:

When using the modes that need the highest pixel rate we support (such as 4k at 60Hz), using a 10 or 12 bpc output will put us over the limit of what we can achieve.

In such a case, let's force our output to be YUV422 so that we can go back down under the required clock rate.

Signed-off-by: Maxime Ripard maxime@cerno.tech

Acked-by: Thomas Zimmermann tzimmermann@suse.de

---

drivers/gpu/drm/vc4/vc4_hdmi.c | 37 +++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index c4f91d39d91c..12eda1e76338 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -1029,6 +1029,41 @@ static unsigned long vc4_hdmi_calc_pixel_rate(struct drm_bridge *bridge, return pixel_rate; }

+static u32 *vc4_hdmi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,

• 				       struct drm_bridge_state *bridge_state,
  

• 				       struct drm_crtc_state *crtc_state,
  

• 				       struct drm_connector_state *conn_state,
  

• 				       unsigned int *num_output_fmts)
  

+{

• struct vc4_hdmi *vc4_hdmi = bridge_to_vc4_hdmi(bridge);
• unsigned long long pixel_rate = vc4_hdmi_calc_pixel_rate(bridge,

• 						 bridge_state,
  

• 						 crtc_state,
  

• 						 conn_state);
  

• /*

• * If our pixel rate is too fast, force YUV422 and hope it works
  

• */
  

• if (pixel_rate > vc4_hdmi->variant->max_pixel_clock) {

• u32 *output_fmts;
  

• output_fmts = kzalloc(sizeof(*output_fmts), GFP_KERNEL);
  

• if (!output_fmts)
  

• 	return NULL;
  

• *output_fmts = MEDIA_BUS_FMT_UYVY8_1X16;
  

• *num_output_fmts = 1;
  

• return output_fmts;
  

• }
• return drm_atomic_helper_bridge_hdmi_get_output_bus_fmts(bridge,

• 						 bridge_state,
  

• 						 crtc_state,
  

• 						 conn_state,
  

• 						 num_output_fmts);
  

+}

• static int vc4_hdmi_bridge_atomic_check(struct drm_bridge *bridge, struct drm_bridge_state *bridge_state, struct drm_crtc_state *crtc_state,

@@ -1088,7 +1123,7 @@ static const struct drm_bridge_funcs vc4_hdmi_bridge_funcs = { .atomic_check = vc4_hdmi_bridge_atomic_check, .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state, .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,

• .atomic_get_output_bus_fmts = drm_atomic_helper_bridge_hdmi_get_output_bus_fmts,

• .atomic_get_output_bus_fmts = vc4_hdmi_bridge_atomic_get_output_bus_fmts, .atomic_reset = drm_atomic_helper_bridge_reset, .mode_valid = vc4_hdmi_bridge_mode_valid, };