[PATCH AUTOSEL 5.4 47/57] drm/msm/mdp5: Configure PP_SYNC_HEIGHT to double the vtotal

[PATCH AUTOSEL 5.4 47/57] drm/msm/mdp5: Configure PP_SYNC_HEIGHT to double the vtotal

[Sasha Levin]

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.org
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);
-- 
2.30.2

[PATCH AUTOSEL 5.4 48/57] drm/msm/mdp5: Do not multiply vclk line count by 100

[Sasha Levin]

From: Marijn Suijten <marijn.suijten@somainline.org>

[ Upstream commit 377569f82ea8228c421cef4da33e056a900b58ca ]

Neither vtotal nor drm_mode_vrefresh contain a value that is
premultiplied by 100 making the x100 variable name incorrect and
resulting in vclks_line to become 100 times larger than it is supposed
to be.  The hardware counts 100 clockticks too many before tearcheck,
leading to severe panel issues on at least the Sony Xperia lineup.

This is likely an artifact from the original MDSS DSI panel driver where
the calculation [1] corrected for a premultiplied reference framerate by
100 [2].  It does not appear that the above values were ever
premultiplied in the history of the DRM MDP5 driver.

With this change applied the value written to the SYNC_CONFIG_VSYNC
register is now identical to downstream kernels.

[1]: https://source.codeaurora.org/quic/la/kernel/msm-3.18/tree/drivers/video/msm/mdss/mdss_mdp_intf_cmd.c?h=LA.UM.8.6.c26-02400-89xx.0#n288
[2]: https://source.codeaurora.org/quic/la/kernel/msm-3.18/tree/drivers/video/msm/mdss/mdss_dsi_panel.c?h=LA.UM.8.6.c26-02400-89xx.0#n1648

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Link: https://lore.kernel.org/r/20210406214726.131534-3-marijn.suijten@somainline.org
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 | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

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 288f18cbf62d..0425400f44db 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_cmd_encoder.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_cmd_encoder.c
@@ -41,7 +41,7 @@ static int pingpong_tearcheck_setup(struct drm_encoder *encoder,
 {
 	struct mdp5_kms *mdp5_kms = get_kms(encoder);
 	struct device *dev = encoder->dev->dev;
-	u32 total_lines_x100, vclks_line, cfg;
+	u32 total_lines, vclks_line, cfg;
 	long vsync_clk_speed;
 	struct mdp5_hw_mixer *mixer = mdp5_crtc_get_mixer(encoder->crtc);
 	int pp_id = mixer->pp;
@@ -51,8 +51,8 @@ static int pingpong_tearcheck_setup(struct drm_encoder *encoder,
 		return -EINVAL;
 	}
 
-	total_lines_x100 = mode->vtotal * drm_mode_vrefresh(mode);
-	if (!total_lines_x100) {
+	total_lines = mode->vtotal * drm_mode_vrefresh(mode);
+	if (!total_lines) {
 		DRM_DEV_ERROR(dev, "%s: vtotal(%d) or vrefresh(%d) is 0\n",
 			      __func__, mode->vtotal, drm_mode_vrefresh(mode));
 		return -EINVAL;
@@ -64,7 +64,7 @@ static int pingpong_tearcheck_setup(struct drm_encoder *encoder,
 							vsync_clk_speed);
 		return -EINVAL;
 	}
-	vclks_line = vsync_clk_speed * 100 / total_lines_x100;
+	vclks_line = vsync_clk_speed / total_lines;
 
 	cfg = MDP5_PP_SYNC_CONFIG_VSYNC_COUNTER_EN
 		| MDP5_PP_SYNC_CONFIG_VSYNC_IN_EN;
-- 
2.30.2