[PATCH AUTOSEL 5.4 083/330] drm/mcde: Handle pending vblank while disabling display

From: Sasha Levin
Date: Thu Sep 17 2020 - 23:10:13 EST

From: Stephan Gerhold <stephan@xxxxxxxxxxx>

[ Upstream commit 97de863673f07f424dd0666aefb4b6ecaba10171 ]

Disabling the display using MCDE currently results in a warning
together with a delay caused by some timeouts:

mcde a0350000.mcde: MCDE display is disabled
------------[ cut here ]------------
WARNING: CPU: 0 PID: 20 at drivers/gpu/drm/drm_atomic_helper.c:2258 drm_atomic_helper_commit_hw_done+0xe0/0xe4
Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support)
Workqueue: events drm_mode_rmfb_work_fn
[<c010f468>] (unwind_backtrace) from [<c010b54c>] (show_stack+0x10/0x14)
[<c010b54c>] (show_stack) from [<c079dd90>] (dump_stack+0x84/0x98)
[<c079dd90>] (dump_stack) from [<c011d1b0>] (__warn+0xb8/0xd4)
[<c011d1b0>] (__warn) from [<c011d230>] (warn_slowpath_fmt+0x64/0xc4)
[<c011d230>] (warn_slowpath_fmt) from [<c0413048>] (drm_atomic_helper_commit_hw_done+0xe0/0xe4)
[<c0413048>] (drm_atomic_helper_commit_hw_done) from [<c04159cc>] (drm_atomic_helper_commit_tail_rpm+0x44/0x6c)
[<c04159cc>] (drm_atomic_helper_commit_tail_rpm) from [<c0415f5c>] (commit_tail+0x50/0x10c)
[<c0415f5c>] (commit_tail) from [<c04160dc>] (drm_atomic_helper_commit+0xbc/0x128)
[<c04160dc>] (drm_atomic_helper_commit) from [<c0430790>] (drm_framebuffer_remove+0x390/0x428)
[<c0430790>] (drm_framebuffer_remove) from [<c0430860>] (drm_mode_rmfb_work_fn+0x38/0x48)
[<c0430860>] (drm_mode_rmfb_work_fn) from [<c01368a8>] (process_one_work+0x1f0/0x43c)
[<c01368a8>] (process_one_work) from [<c0136d48>] (worker_thread+0x254/0x55c)
[<c0136d48>] (worker_thread) from [<c013c014>] (kthread+0x124/0x150)
[<c013c014>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
Exception stack(0xeb14dfb0 to 0xeb14dff8)
dfa0: 00000000 00000000 00000000 00000000
dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
dfe0: 00000000 00000000 00000000 00000000 00000013 00000000
---[ end trace 314909bcd4c7d50c ]---
[drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:32:crtc-0] flip_done timed out
[drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:34:DSI-1] flip_done timed out
[drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:31:plane-0] flip_done timed out

The reason for this is that there is a vblank event pending, but we
never handle it after disabling the vblank interrupts.

Check if there is an vblank event pending when disabling the display,
and clear it by sending a fake vblank event in that case.

Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20191106165835.2863-8-stephan@xxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/gpu/drm/mcde/mcde_display.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/mcde/mcde_display.c b/drivers/gpu/drm/mcde/mcde_display.c
index 751454ae3cd10..28ed506285018 100644
--- a/drivers/gpu/drm/mcde/mcde_display.c
+++ b/drivers/gpu/drm/mcde/mcde_display.c
@@ -946,6 +946,7 @@ static void mcde_display_disable(struct drm_simple_display_pipe *pipe)
struct drm_crtc *crtc = &pipe->crtc;
struct drm_device *drm = crtc->dev;
struct mcde *mcde = drm->dev_private;
+ struct drm_pending_vblank_event *event;

if (mcde->te_sync)
@@ -953,6 +954,15 @@ static void mcde_display_disable(struct drm_simple_display_pipe *pipe)
/* Disable FIFO A flow */
mcde_disable_fifo(mcde, MCDE_FIFO_A, true);

+ event = crtc->state->event;
+ if (event) {
+ crtc->state->event = NULL;
+ spin_lock_irq(&crtc->dev->event_lock);
+ drm_crtc_send_vblank_event(crtc, event);
+ spin_unlock_irq(&crtc->dev->event_lock);
+ }
dev_info(drm->dev, "MCDE display is disabled\n");