On 7/20/2023 2:46 PM, Lisovskiy, Stanislav wrote:
On Thu, Jul 13, 2023 at 04:03:33PM +0530, Ankit Nautiyal wrote:
Currently we assume 2 Pixels Per Clock (PPC) while computing
plane cdclk and min_cdlck. In cases where DSC single engine
is used the throughput is 1 PPC.
So account for the above case, while computing cdclk.
v2: Use helper to get the adjusted pixel rate.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_cdclk.c | 2 +-
drivers/gpu/drm/i915/display/intel_vdsc.c | 12 ++++++++++++
drivers/gpu/drm/i915/display/intel_vdsc.h | 2 ++
drivers/gpu/drm/i915/display/skl_universal_plane.c | 4 ++--
4 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index dcc1f6941b60..701909966545 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -2508,7 +2508,7 @@ static int intel_pixel_rate_to_cdclk(const struct intel_crtc_state *crtc_state)
int pixel_rate = crtc_state->pixel_rate;
if (DISPLAY_VER(dev_priv) >= 10)
- return DIV_ROUND_UP(pixel_rate, 2);
+ return intel_dsc_get_adjusted_pixel_rate(crtc_state, pixel_rate);
else if (DISPLAY_VER(dev_priv) == 9 ||
IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
return pixel_rate;
diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
index 9d76c2756784..bbfdbf06da68 100644
--- a/drivers/gpu/drm/i915/display/intel_vdsc.c
+++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
@@ -1038,3 +1038,15 @@ void intel_dsc_get_config(struct intel_crtc_state *crtc_state)
out:
intel_display_power_put(dev_priv, power_domain, wakeref);
}
+
+int intel_dsc_get_adjusted_pixel_rate(const struct intel_crtc_state *crtc_state, int pixel_rate)
+{
+ /*
+ * If single VDSC engine is used, it uses one pixel per clock
+ * otherwise we use two pixels per clock.
+ */
+ if (crtc_state->dsc.compression_enable && !crtc_state->dsc.dsc_split)
+ return pixel_rate;
+
+ return DIV_ROUND_UP(pixel_rate, 2);
+}
diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.h b/drivers/gpu/drm/i915/display/intel_vdsc.h
index 2cc41ff08909..3bb4b1980b6b 100644
--- a/drivers/gpu/drm/i915/display/intel_vdsc.h
+++ b/drivers/gpu/drm/i915/display/intel_vdsc.h
@@ -28,4 +28,6 @@ void intel_dsc_dsi_pps_write(struct intel_encoder *encoder,
void intel_dsc_dp_pps_write(struct intel_encoder *encoder,
const struct intel_crtc_state *crtc_state);
+int intel_dsc_get_adjusted_pixel_rate(const struct intel_crtc_state *crtc_state, int pixel_rate);
+
#endif /* __INTEL_VDSC_H__ */
diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
index 6b01a0b68b97..9eeb25ec4be9 100644
--- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
+++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
@@ -17,6 +17,7 @@
#include "intel_fb.h"
#include "intel_fbc.h"
#include "intel_psr.h"
+#include "intel_vdsc.h"
#include "skl_scaler.h"
#include "skl_universal_plane.h"
#include "skl_watermark.h"
@@ -263,8 +264,7 @@ static int icl_plane_min_cdclk(const struct intel_crtc_state *crtc_state,
{
unsigned int pixel_rate = intel_plane_pixel_rate(crtc_state, plane_state);
- /* two pixels per clock */
- return DIV_ROUND_UP(pixel_rate, 2);
+ return intel_dsc_get_adjusted_pixel_rate(crtc_state, pixel_rate);
Hi Ankit,
I think the thing what you are taking of is already handled here in intel_cdclk.c:
/*
* When we decide to use only one VDSC engine, since
* each VDSC operates with 1 ppc throughput, pixel clock
* cannot be higher than the VDSC clock (cdclk)
* If there 2 VDSC engines, then pixel clock can't be higher than
* VDSC clock(cdclk) * 2 and so on.
*/
if (crtc_state->dsc.compression_enable) {
int num_vdsc_instances = intel_dsc_get_num_vdsc_instances(crtc_state);
min_cdclk = max_t(int, min_cdclk,
DIV_ROUND_UP(crtc_state->pixel_rate,
num_vdsc_instances));
}
As far as I understand this condition is coming from the pixel clock
limitation as an input to the splitter (Bspec: 49259):
Pipe BW check:
Pixel clock < PPC * CDCLK frequency * Number of pipes joined
PPC = 1 or 2 depending on number of DSC engines used within the pipe.
So it implies CDCLK frequency > Pixel clock / (PPC * Number of pipes joined)
num_vdsc_instances is actually giving us (PPC * number of pipes joined).
I completely agree that there will be no effect of the change on the
min_cdclk that gets computed in any case, whether DSC, 1 engine, 2
engine, bigjoiner or no DSC.
Only thing is for the case where 1 DSC engine is used, what
intel_pixel_rate_to_cdclk return will be different, and its due to the
fact that pipe is driven with 1PPC.
But as I said, the min_cdclk computed will be same as without patch. So
we can certainly do away with this change, and I can drop this from the
patch.
But in case of icl_plane_min_cdclk, currently we are dividing the
plane_pixel_rate by 2, citing that we use 2 pixel per clock, to get the
plane_min_cdclk.
Should this not be 1 PPC in case where single DSC engine is used? In
that case plane_min_cdclk will be double. Should we keep the change only
for plane_min_cdclk then?
Regards,
Ankit
Also even if something still have to be done here, I think we should preferrably
deal with anything related to DSC in a single place, to prevent any kind of
confusion(when those checks are scattered in different places, it is way more easy to forget/not notice something)
I think intel_pixel_rate_to_cdclk isn't supposed to know anything about DSC or any other specifics like audio checks and etc - it is
just dealing with the "default" uncompressed case.
Any other additional limitations or checks we apply after those, as there are
quite many anyway.
Stan
}
static void
--
2.40.1
