Hi, Hsin-yi:
On Wed, 2019-03-20 at 15:18 +0800, Hsin-Yi Wang wrote:
> mtk_dsi_stop() should be called after mtk_drm_crtc_atomic_disable(), which
> needs
> ovl irq for drm_crtc_wait_one_vblank(), since after mtk_dsi_stop() is called,
> ovl irq will be disabled. If drm_crtc_wait_one_vblank() is called after last
> irq, it will timeout with this message: "vblank wait timed out on crtc 0".
> This
> happens sometimes when turning off the screen.
>
> In drm_atomic_helper.c#disable_outputs(),
> the calling sequence when turning off the screen is:
>
> 1. mtk_dsi_encoder_disable()
> --> mtk_output_dsi_disable()
> --> mtk_dsi_stop(); // sometimes make vblank timeout in atomic_disable
> --> mtk_dsi_poweroff();
> 2. mtk_drm_crtc_atomic_disable()
> --> drm_crtc_wait_one_vblank();
> ...
> --> mtk_dsi_ddp_stop()
> --> mtk_dsi_poweroff();
>
> mtk_dsi_poweroff() has reference count design, change to make mtk_dsi_stop()
> called in mtk_dsi_poweroff() when refcount is 0.
>
> Fixes: 0707632b5bac ("drm/mediatek: update DSI sub driver flow for sending
> commands to panel")
> Signed-off-by: Hsin-Yi Wang <hsi...@chromium.org>
> ---
> change log:
> v1->v2:
> * update commit message.
> * call mtk_dsi_stop() in mtk_dsi_poweroff() when refcount is 0.
> ---
> drivers/gpu/drm/mediatek/mtk_dsi.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index b00eb2d2e086..e152f37af57d 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -630,6 +630,8 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
> if (--dsi->refcount != 0)
> return;
>
> + mtk_dsi_stop(dsi);
> +
> if (!mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500)) {
> if (dsi->panel) {
> if (drm_panel_unprepare(dsi->panel)) {
I think you just move mtk_dsi_stop() into mtk_dsi_poweroff() would works
fine, but I would rather like calling mtk_dsi_start() and mtk_dsi_stop()
in a symmetric manner. That means you may also move below functions into
mtk_dsi_poweron():
mtk_dsi_set_mode(dsi);
mtk_dsi_clk_hs_mode(dsi, 1);
mtk_dsi_start(dsi);
> @@ -696,7 +698,6 @@ static void mtk_output_dsi_disable(struct mtk_dsi *dsi)
> }
> }
>
> - mtk_dsi_stop(dsi);
> mtk_dsi_poweroff(dsi);
>
> dsi->enabled = false;
> @@ -1178,6 +1179,8 @@ static int mtk_dsi_remove(struct platform_device *pdev)
> struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>
> mtk_output_dsi_disable(dsi);
> + mtk_dsi_stop(dsi);
> + mtk_dsi_poweroff(dsi);
I think mtk_output_dsi_disable() would call mtk_dsi_poweroff(), and
mtk_dsi_poweroff() would call mtk_dsi_stop(), so these two line are
redundant. And I think you should remove mtk_dsi_stop() in
mtk_output_dsi_disable(), why not in this patch?
Regards,
CK
> component_del(&pdev->dev, &mtk_dsi_component_ops);
>
> return 0;
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