From: Marek Vasut <[email protected]>

[ Upstream commit ebd267b2e3c25d5f93a08528b47c036569eb8744 ]

Add missing pm_runtime_get_sync() into ltdc_crtc_atomic_enable() to
match pm_runtime_put_sync() in ltdc_crtc_atomic_disable(), otherwise
the LTDC might suspend via runtime PM, disable clock, and then fail
to resume later on.

The test which triggers it is roughly -- run qt5 application which
uses eglfs platform and etnaviv, stop the application, sleep for 15
minutes, run the application again. This leads to a timeout waiting
for vsync, because the LTDC has suspended, but did not resume.

Fixes: 35ab6cfbf211 ("drm/stm: support runtime power management")
Signed-off-by: Marek Vasut <[email protected]>
Cc: Yannick Fertré <[email protected]>
Cc: Philippe Cornu <[email protected]>
Cc: Benjamin Gaignard <[email protected]>
Cc: Vincent Abriou <[email protected]>
Cc: Maxime Coquelin <[email protected]>
Cc: Alexandre Torgue <[email protected]>
To: [email protected]
Cc: [email protected]
Cc: [email protected]
Acked-by: Philippe Cornu <[email protected]>
Tested-by: Yannick Fertre <[email protected]>
Signed-off-by: Benjamin Gaignard <[email protected]>
Link: 
https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
---
 drivers/gpu/drm/stm/ltdc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index df585fe64f614..60ffe5bbc1294 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -425,9 +425,12 @@ static void ltdc_crtc_atomic_enable(struct drm_crtc *crtc,
                                    struct drm_crtc_state *old_state)
 {
        struct ltdc_device *ldev = crtc_to_ltdc(crtc);
+       struct drm_device *ddev = crtc->dev;
 
        DRM_DEBUG_DRIVER("\n");
 
+       pm_runtime_get_sync(ddev->dev);
+
        /* Sets the background color value */
        reg_write(ldev->regs, LTDC_BCCR, BCCR_BCBLACK);
 
-- 
2.25.1



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