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drm/vc4: crtc: Increase setup cost in core clock calculation to handle extreme reduced blanking

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The formula that determines the core clock requirement based on pixel
clock and blanking has been determined experimentally to minimise the
clock while supporting all modes we've seen.

A new reduced blanking mode (4kp60 at 533MHz rather than the standard
594MHz) has been seen that doesn't produce a high enough clock and
results in "flip_done timed out" error.

Increase the setup cost in the formula to make this work. The result is
a reduced blanking mode increases by up to 7MHz while leaving the
standard timing
mode untouched

Link: https://github.com/raspberrypi/linux/issues/4446
Fixes: 16e101051f ("drm/vc4: Increase the core clock based on HVS load")
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20230127145558.446123-1-maxime@cerno.tech
This commit is contained in:
Dom Cobley 2023-01-27 15:55:58 +01:00 committed by Maxime Ripard
parent 7fa846b95c
commit 247a631f9c
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GPG key ID: E3EF0D6F671851C5
1 changed files with 1 additions and 1 deletions
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2
drivers/gpu/drm/vc4/vc4_crtc.c
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@ -711,7 +711,7 @@ static int vc4_crtc_atomic_check(struct drm_crtc *crtc,
struct vc4_encoder *vc4_encoder = to_vc4_encoder(encoder);
if (vc4_encoder->type == VC4_ENCODER_TYPE_HDMI0) {
vc4_state->hvs_load = max(mode->clock * mode->hdisplay / mode->htotal + 1000,
vc4_state->hvs_load = max(mode->clock * mode->hdisplay / mode->htotal + 8000,
mode->clock * 9 / 10) * 1000;
} else {
vc4_state->hvs_load = mode->clock * 1000;