From: Marijn Suijten marijn.suijten@somainline.org
[ Upstream commit 2ad52bdb220de5ab348098e3482b01235d15a842 ]
Leaving this at a close-to-maximum register value 0xFFF0 means it takes very long for the MDSS to generate a software vsync interrupt when the hardware TE interrupt doesn't arrive. Configuring this to double the vtotal (like some downstream kernels) leads to a frame to take at most twice before the vsync signal, until hardware TE comes up.
In this case the hardware interrupt responsible for providing this signal - "disp-te" gpio - is not hooked up to the mdp5 vsync/pp logic at all. This solves severe panel update issues observed on at least the Xperia Loire and Tone series, until said gpio is properly hooked up to an irq.
Suggested-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org Link: https://lore.kernel.org/r/20210406214726.131534-2-marijn.suijten@somainline.... Signed-off-by: Rob Clark robdclark@chromium.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/msm/disp/mdp5/mdp5_cmd_encoder.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_cmd_encoder.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_cmd_encoder.c index eeef41fcd4e1..288f18cbf62d 100644 --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_cmd_encoder.c +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_cmd_encoder.c @@ -70,9 +70,17 @@ static int pingpong_tearcheck_setup(struct drm_encoder *encoder, | MDP5_PP_SYNC_CONFIG_VSYNC_IN_EN; cfg |= MDP5_PP_SYNC_CONFIG_VSYNC_COUNT(vclks_line);
+ /* + * Tearcheck emits a blanking signal every vclks_line * vtotal * 2 ticks on + * the vsync_clk equating to roughly half the desired panel refresh rate. + * This is only necessary as stability fallback if interrupts from the + * panel arrive too late or not at all, but is currently used by default + * because these panel interrupts are not wired up yet. + */ mdp5_write(mdp5_kms, REG_MDP5_PP_SYNC_CONFIG_VSYNC(pp_id), cfg); mdp5_write(mdp5_kms, - REG_MDP5_PP_SYNC_CONFIG_HEIGHT(pp_id), 0xfff0); + REG_MDP5_PP_SYNC_CONFIG_HEIGHT(pp_id), (2 * mode->vtotal)); + mdp5_write(mdp5_kms, REG_MDP5_PP_VSYNC_INIT_VAL(pp_id), mode->vdisplay); mdp5_write(mdp5_kms, REG_MDP5_PP_RD_PTR_IRQ(pp_id), mode->vdisplay + 1);