From 9625604cebcb3f5be2e692408274734e8ae63979 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Fri, 13 Feb 2015 21:03:42 +0100 Subject: [PATCH] drm/irq: Add drm_crtc_vblank_reset MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit At driver load we need to tell the vblank code about the state of the pipes, so that the logic around reject vblank_get when the pipe is off works correctly. Thus far i915 used drm_vblank_off, but one of the side-effects of it is that it also saves the vblank counter. And for that it calls down into the ->get_vblank_counter hook. Which isn't really a good idea when the pipe is off for a few reasons: - With runtime pm the register might not respond. - If the pipe is off some datastructures might not be around or unitialized. The later is what blew up on gen3: We look at intel_crtc->config to compute the vblank counter, and for a disabled pipe at boot-up that's just not there. Thus far this was papered over by a check for intel_crtc->active, but I want to get rid of that (since it's fairly race, vblank hooks are called from all kinds of places). So prep for that by adding a _reset functions which only does what we really need to be done at driver load: Mark the vblank pipe as off, but don't do any vblank counter saving or event flushing - neither of that is required. v2: Clarify the code flow slightly as suggested by Ville. v3: Fix kerneldoc spelling, spotted by Laurent. Cc: Ville Syrjälä Cc: Laurent Pinchart Cc: Imre Deak Reviewed-by: Imre Deak (v2) Acked-by: Dave Airlie Acked-by: Laurent Pinchart Signed-off-by: Daniel Vetter --- drivers/gpu/drm/drm_irq.c | 32 ++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_display.c | 6 +++--- include/drm/drmP.h | 1 + 3 files changed, 36 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 75647e7f012b..e78a1f5cad9c 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1225,6 +1225,38 @@ void drm_crtc_vblank_off(struct drm_crtc *crtc) } EXPORT_SYMBOL(drm_crtc_vblank_off); +/** + * drm_crtc_vblank_reset - reset vblank state to off on a CRTC + * @crtc: CRTC in question + * + * Drivers can use this function to reset the vblank state to off at load time. + * Drivers should use this together with the drm_crtc_vblank_off() and + * drm_crtc_vblank_on() functions. The difference compared to + * drm_crtc_vblank_off() is that this function doesn't save the vblank counter + * and hence doesn't need to call any driver hooks. + */ +void drm_crtc_vblank_reset(struct drm_crtc *drm_crtc) +{ + struct drm_device *dev = drm_crtc->dev; + unsigned long irqflags; + int crtc = drm_crtc_index(drm_crtc); + struct drm_vblank_crtc *vblank = &dev->vblank[crtc]; + + spin_lock_irqsave(&dev->vbl_lock, irqflags); + /* + * Prevent subsequent drm_vblank_get() from enabling the vblank + * interrupt by bumping the refcount. + */ + if (!vblank->inmodeset) { + atomic_inc(&vblank->refcount); + vblank->inmodeset = 1; + } + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); + + WARN_ON(!list_empty(&dev->vblank_event_list)); +} +EXPORT_SYMBOL(drm_crtc_vblank_reset); + /** * drm_vblank_on - enable vblank events on a CRTC * @dev: DRM device diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 3b0fe9f1f3c9..b901b00a8f2e 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -13316,11 +13316,11 @@ static void intel_sanitize_crtc(struct intel_crtc *crtc) I915_WRITE(reg, I915_READ(reg) & ~PIPECONF_FRAME_START_DELAY_MASK); /* restore vblank interrupts to correct state */ + drm_crtc_vblank_reset(&crtc->base); if (crtc->active) { update_scanline_offset(crtc); - drm_vblank_on(dev, crtc->pipe); - } else - drm_vblank_off(dev, crtc->pipe); + drm_crtc_vblank_on(&crtc->base); + } /* We need to sanitize the plane -> pipe mapping first because this will * disable the crtc (and hence change the state) if it is wrong. Note diff --git a/include/drm/drmP.h b/include/drm/drmP.h index e928625a9da0..54c6ea1e5866 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -922,6 +922,7 @@ extern void drm_crtc_wait_one_vblank(struct drm_crtc *crtc); extern void drm_vblank_off(struct drm_device *dev, int crtc); extern void drm_vblank_on(struct drm_device *dev, int crtc); extern void drm_crtc_vblank_off(struct drm_crtc *crtc); +extern void drm_crtc_vblank_reset(struct drm_crtc *crtc); extern void drm_crtc_vblank_on(struct drm_crtc *crtc); extern void drm_vblank_cleanup(struct drm_device *dev); -- 2.20.1