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Date: Thu, 21 Mar 2019 09:28:42 +0800 From: CK Hu <ck.hu@...iatek.com> To: Hsin-Yi Wang <hsinyi@...omium.org> CC: <linux-arm-kernel@...ts.infradead.org>, Philipp Zabel <p.zabel@...gutronix.de>, David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>, Matthias Brugger <matthias.bgg@...il.com>, <dri-devel@...ts.freedesktop.org>, <linux-mediatek@...ts.infradead.org>, <linux-kernel@...r.kernel.org> Subject: Re: [PATCH v2] gpu/drm: mediatek: call mtk_dsi_stop() after mtk_drm_crtc_atomic_disable() 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 <hsinyi@...omium.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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