You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
94 lines
3.1 KiB
94 lines
3.1 KiB
8 years ago
|
From d7f32f81cf7579ac7d13127db88e789ea864824c Mon Sep 17 00:00:00 2001
|
||
|
|
From: Derek Foreman <derekf@osg.samsung.com>
|
||
|
|
Date: Thu, 24 Nov 2016 12:11:55 -0600
|
||
|
|
Subject: [PATCH] drm/vc4: Fix race between page flip completion event and
|
||
|
|
clean-up
|
||
|
|
|
||
|
|
There was a small window where a userspace program could submit
|
||
|
|
a pageflip after receiving a pageflip completion event yet still
|
||
|
|
receive EBUSY.
|
||
|
|
|
||
|
|
Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
|
||
|
|
Signed-off-by: Eric Anholt <eric@anholt.net>
|
||
|
|
Reviewed-by: Eric Anholt <eric@anholt.net>
|
||
|
|
Reviewed-by: Daniel Stone <daniels@collabora.com>
|
||
|
|
(cherry picked from commit 26fc78f6fef39b9d7a15def5e7e9826ff68303f4)
|
||
|
|
---
|
||
|
|
drivers/gpu/drm/vc4/vc4_crtc.c | 8 ++++++++
|
||
|
|
drivers/gpu/drm/vc4/vc4_drv.h | 1 +
|
||
|
|
drivers/gpu/drm/vc4/vc4_kms.c | 33 +++++++++++++++++++++++++--------
|
||
|
|
3 files changed, 34 insertions(+), 8 deletions(-)
|
||
|
|
|
||
|
|
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
|
||
|
|
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
|
||
|
|
@@ -682,6 +682,14 @@ void vc4_disable_vblank(struct drm_devic
|
||
|
|
CRTC_WRITE(PV_INTEN, 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
+/* Must be called with the event lock held */
|
||
|
|
+bool vc4_event_pending(struct drm_crtc *crtc)
|
||
|
|
+{
|
||
|
|
+ struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
|
||
|
|
+
|
||
|
|
+ return !!vc4_crtc->event;
|
||
|
|
+}
|
||
|
|
+
|
||
|
|
static void vc4_crtc_handle_page_flip(struct vc4_crtc *vc4_crtc)
|
||
|
|
{
|
||
|
|
struct drm_crtc *crtc = &vc4_crtc->base;
|
||
|
|
--- a/drivers/gpu/drm/vc4/vc4_drv.h
|
||
|
|
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
|
||
|
|
@@ -445,6 +445,7 @@ int vc4_bo_stats_debugfs(struct seq_file
|
||
|
|
extern struct platform_driver vc4_crtc_driver;
|
||
|
|
int vc4_enable_vblank(struct drm_device *dev, unsigned int crtc_id);
|
||
|
|
void vc4_disable_vblank(struct drm_device *dev, unsigned int crtc_id);
|
||
|
|
+bool vc4_event_pending(struct drm_crtc *crtc);
|
||
|
|
int vc4_crtc_debugfs_regs(struct seq_file *m, void *arg);
|
||
|
|
int vc4_crtc_get_scanoutpos(struct drm_device *dev, unsigned int crtc_id,
|
||
|
|
unsigned int flags, int *vpos, int *hpos,
|
||
|
|
--- a/drivers/gpu/drm/vc4/vc4_kms.c
|
||
|
|
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
|
||
|
|
@@ -119,17 +119,34 @@ static int vc4_atomic_commit(struct drm_
|
||
|
|
|
||
|
|
/* Make sure that any outstanding modesets have finished. */
|
||
|
|
if (nonblock) {
|
||
|
|
- ret = down_trylock(&vc4->async_modeset);
|
||
|
|
- if (ret) {
|
||
|
|
+ struct drm_crtc *crtc;
|
||
|
|
+ struct drm_crtc_state *crtc_state;
|
||
|
|
+ unsigned long flags;
|
||
|
|
+ bool busy = false;
|
||
|
|
+
|
||
|
|
+ /*
|
||
|
|
+ * If there's an undispatched event to send then we're
|
||
|
|
+ * obviously still busy. If there isn't, then we can
|
||
|
|
+ * unconditionally wait for the semaphore because it
|
||
|
|
+ * shouldn't be contended (for long).
|
||
|
|
+ *
|
||
|
|
+ * This is to prevent a race where queuing a new flip
|
||
|
|
+ * from userspace immediately on receipt of an event
|
||
|
|
+ * beats our clean-up and returns EBUSY.
|
||
|
|
+ */
|
||
|
|
+ spin_lock_irqsave(&dev->event_lock, flags);
|
||
|
|
+ for_each_crtc_in_state(state, crtc, crtc_state, i)
|
||
|
|
+ busy |= vc4_event_pending(crtc);
|
||
|
|
+ spin_unlock_irqrestore(&dev->event_lock, flags);
|
||
|
|
+ if (busy) {
|
||
|
|
kfree(c);
|
||
|
|
return -EBUSY;
|
||
|
|
}
|
||
|
|
- } else {
|
||
|
|
- ret = down_interruptible(&vc4->async_modeset);
|
||
|
|
- if (ret) {
|
||
|
|
- kfree(c);
|
||
|
|
- return ret;
|
||
|
|
- }
|
||
|
|
+ }
|
||
|
|
+ ret = down_interruptible(&vc4->async_modeset);
|
||
|
|
+ if (ret) {
|
||
|
|
+ kfree(c);
|
||
|
|
+ return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = drm_atomic_helper_prepare_planes(dev, state);
|