Re: [PATCH v2 07/15] drm/mxsfb: Fix the vblank events
From: Daniel Vetter <hidden>
Date: 2019-08-14 17:32:02
Also in:
dri-devel, linux-devicetree, lkml
On Wed, Aug 14, 2019 at 01:48:43PM +0300, Robert Chiras wrote:
Currently, the vblank support is not correctly implemented in MXSFB_DRM driver. The call to drm_vblank_init is made with mode_config.num_crtc which at that time is 0. Because of this, vblank is not activated, so there won't be any vblank event submitted. For example, when running modetest with the '-v' parameter will result in an astronomical refresh rate (10000+ Hz), because of that.
Uh, that sounds a bit like a bug somewhere. If vblank doesn't work, we should give userspace an error back. Maybe we need more checks in drm_vblank_init()? Can you pls look into that?
quoted hunk ↗ jump to hunk
Signed-off-by: Robert Chiras <robert.chiras@nxp.com> --- drivers/gpu/drm/mxsfb/mxsfb_drv.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c index 2743975..829abec 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c@@ -38,6 +38,9 @@ #include "mxsfb_drv.h" #include "mxsfb_regs.h" +/* The eLCDIF max possible CRTCs */ +#define MAX_CRTCS 1 + enum mxsfb_devtype { MXSFB_V3, MXSFB_V4,@@ -138,6 +141,8 @@ static void mxsfb_pipe_enable(struct drm_simple_display_pipe *pipe, mxsfb->connector = &mxsfb->panel_connector; } + drm_crtc_vblank_on(&pipe->crtc); + pm_runtime_get_sync(drm->dev); drm_panel_prepare(mxsfb->panel); mxsfb_crtc_enable(mxsfb);@@ -164,6 +169,8 @@ static void mxsfb_pipe_disable(struct drm_simple_display_pipe *pipe) } spin_unlock_irq(&drm->event_lock); + drm_crtc_vblank_off(&pipe->crtc); + if (mxsfb->connector != &mxsfb->panel_connector) mxsfb->connector = NULL; }@@ -246,7 +253,7 @@ static int mxsfb_load(struct drm_device *drm, unsigned long flags) pm_runtime_enable(drm->dev); - ret = drm_vblank_init(drm, drm->mode_config.num_crtc); + ret = drm_vblank_init(drm, MAX_CRTCS); if (ret < 0) { dev_err(drm->dev, "Failed to initialise vblank\n"); goto err_vblank;@@ -269,6 +276,8 @@ static int mxsfb_load(struct drm_device *drm, unsigned long flags) goto err_vblank; } + drm_crtc_vblank_off(&mxsfb->pipe.crtc);
Are you sure you need this one here? vblanks should be off after drm_vblank_init() is called. Thanks, Daniel
+ /* * Attach panel only if there is one. * If there is no panel attach, it must be a bridge. In this case, we -- 2.7.4
-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel