[PATCH 5.19 150/207] drm/mediatek: dsi: Move mtk_dsi_stop() call back to mtk_dsi_poweroff()

Greg Kroah-Hartman
2022-09-26T11:58:19Z

From: Nícolas F. R. A. Prado <nfraprado@collabora.com>

[ Upstream commit 90144dd8b0d137d9e78ef34b3c418e51a49299ad ]

As the comment right before the mtk_dsi_stop() call advises,
mtk_dsi_stop() should only be called after
mtk_drm_crtc_atomic_disable(). That's because that function calls
drm_crtc_wait_one_vblank(), which requires the vblank irq to be enabled.

Previously mtk_dsi_stop(), being in mtk_dsi_poweroff() and guarded by a
refcount, would only be called at the end of
mtk_drm_crtc_atomic_disable(), through the call to mtk_crtc_ddp_hw_fini().
Commit cde7e2e35c28 ("drm/mediatek: Separate poweron/poweroff from
enable/disable and define new funcs") moved the mtk_dsi_stop() call to
mtk_output_dsi_disable(), causing it to be called before
mtk_drm_crtc_atomic_disable(), and consequently generating vblank
timeout warnings during suspend.

Move the mtk_dsi_stop() call back to mtk_dsi_poweroff() so that we have
a working vblank irq during mtk_drm_crtc_atomic_disable() and stop
getting vblank timeout warnings.

Fixes: cde7e2e35c28 ("drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Link: http://lists.infradead.org/pipermail/linux-mediatek/2022-August/046713.html
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index e98b4aca2cb9..9a3b86c29b50 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -685,6 +685,16 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
if (--dsi->refcount != 0)
return;

+ /*
+ * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
+ * mtk_dsi_stop() should be called after mtk_drm_crtc_atomic_disable(),
+ * which needs irq for vblank, and mtk_dsi_stop() will disable irq.
+ * mtk_dsi_start() needs to be called in mtk_output_dsi_enable(),
+ * after dsi is fully set.
+ */
+ mtk_dsi_stop(dsi);
+
+ mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
mtk_dsi_reset_engine(dsi);
mtk_dsi_lane0_ulp_mode_enter(dsi);
mtk_dsi_clk_ulp_mode_enter(dsi);
@@ -735,17 +745,6 @@ static void mtk_output_dsi_disable(struct mtk_dsi *dsi)
if (!dsi->enabled)
return;

- /*
- * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
- * mtk_dsi_stop() should be called after mtk_drm_crtc_atomic_disable(),
- * which needs irq for vblank, and mtk_dsi_stop() will disable irq.
- * mtk_dsi_start() needs to be called in mtk_output_dsi_enable(),
- * after dsi is fully set.
- */
- mtk_dsi_stop(dsi);
-
- mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
-
dsi->enabled = false;
}

--
2.35.1