Patch "drm/vc4: kms: Use maximum FIFO load for the HVS clock rate" has been added to the 5.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/vc4: kms: Use maximum FIFO load for the HVS clock rate

to the 5.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-vc4-kms-use-maximum-fifo-load-for-the-hvs-clock-.patch
and it can be found in the queue-5.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 262bf69fe21ab135036f42c46049b796595e2bd2
Author: Maxime Ripard <maxime@xxxxxxxxxx>
Date:   Mon Jun 13 16:47:30 2022 +0200

    drm/vc4: kms: Use maximum FIFO load for the HVS clock rate
    
    [ Upstream commit 1701a23a4ef0993964ccc2f2d5d13f83a5ff4c70 ]
    
    The core clock computation takes into account both the load due to the
    input (ie, planes) and its output (ie, encoders).
    
    However, while the input load needs to consider all the planes, and thus
    sum all of their associated loads, the output happens mostly in
    parallel.
    
    Therefore, we need to consider only the maximum of all the output loads,
    and not the sum like we were doing. This resulted in a clock rate way
    too high which could be discarded for being too high by the clock
    framework.
    
    Since recent changes, the clock framework will even downright reject it,
    leading to a core clock being too low for its current needs.
    
    Fixes: 16e101051f32 ("drm/vc4: Increase the core clock based on HVS load")
    Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
    Reviewed-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20220613144800.326124-4-maxime@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 893d831b24aa..b7353d4c0811 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -950,7 +950,9 @@ vc4_core_clock_atomic_check(struct drm_atomic_state *state)
 			continue;
 
 		num_outputs++;
-		cob_rate += hvs_new_state->fifo_state[i].fifo_load;
+		cob_rate = max_t(unsigned long,
+				 hvs_new_state->fifo_state[i].fifo_load,
+				 cob_rate);
 	}
 
 	pixel_rate = load_state->hvs_load;