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drm/rockchip: cancel pending vblanks on close 

When closing the DRM device while a vblank is pending, we access
file_priv after it has been free'd, which gives:

  Unable to handle kernel NULL pointer dereference at virtual address 00000000
  ...
  PC is at __list_add+0x5c/0xe8
  LR is at send_vblank_event+0x54/0x1f0
  ...
  [<c02952e8>] (__list_add) from [<c031a7b4>] (send_vblank_event+0x54/0x1f0)
  [<c031a760>] (send_vblank_event) from [<c031a9c0>] (drm_send_vblank_event+0x70/0x78)
  [<c031a950>] (drm_send_vblank_event) from [<c031a9f8>] (drm_crtc_send_vblank_event+0x30/0x34)
  [<c031a9c8>] (drm_crtc_send_vblank_event) from [<c0339ad8>] (vop_isr+0x224/0x28c)
  [<c03398b4>] (vop_isr) from [<c0081780>] (handle_irq_event_percpu+0x12c/0x3e4)

This can be triggered somewhat reliably with:

	modetest -M rockchip -v -s ...

Add a preclose hook to the driver so that we can discard any pending
vblank events when the device is closed.

Signed-off-by: John Keeping <john@metanate.com>
This commit is contained in:
John Keeping 2016-03-11 17:21:17 +00:00 committed by Mark Yao
parent 92915da647
commit f135046e51
3 changed files with 43 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/gpu/drm/rockchip/rockchip_drm_drv.c
View File

@ -251,6 +251,27 @@ static int rockchip_drm_unload(struct drm_device *drm_dev)
return 0;
}
static void rockchip_drm_crtc_cancel_pending_vblank(struct drm_crtc *crtc,
struct drm_file *file_priv)
{
struct rockchip_drm_private *priv = crtc->dev->dev_private;
int pipe = drm_crtc_index(crtc);
if (pipe < ROCKCHIP_MAX_CRTC &&
priv->crtc_funcs[pipe] &&
priv->crtc_funcs[pipe]->cancel_pending_vblank)
priv->crtc_funcs[pipe]->cancel_pending_vblank(crtc, file_priv);
}
static void rockchip_drm_preclose(struct drm_device *dev,
struct drm_file *file_priv)
{
struct drm_crtc *crtc;
list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
rockchip_drm_crtc_cancel_pending_vblank(crtc, file_priv);
}
void rockchip_drm_lastclose(struct drm_device *dev)
{
struct rockchip_drm_private *priv = dev->dev_private;
@ -281,6 +302,7 @@ static struct drm_driver rockchip_drm_driver = {
DRIVER_PRIME | DRIVER_ATOMIC,
.load = rockchip_drm_load,
.unload = rockchip_drm_unload,
.preclose = rockchip_drm_preclose,
.lastclose = rockchip_drm_lastclose,
.get_vblank_counter = drm_vblank_no_hw_counter,
.enable_vblank = rockchip_drm_crtc_enable_vblank,

1
drivers/gpu/drm/rockchip/rockchip_drm_drv.h
View File

@ -40,6 +40,7 @@ struct rockchip_crtc_funcs {
int (*enable_vblank)(struct drm_crtc *crtc);
void (*disable_vblank)(struct drm_crtc *crtc);
void (*wait_for_update)(struct drm_crtc *crtc);
void (*cancel_pending_vblank)(struct drm_crtc *crtc, struct drm_file *file_priv);
};
struct rockchip_atomic_commit {

20
drivers/gpu/drm/rockchip/rockchip_drm_vop.c
View File

@ -875,10 +875,30 @@ static void vop_crtc_wait_for_update(struct drm_crtc *crtc)
WARN_ON(!wait_for_completion_timeout(&vop->wait_update_complete, 100));
}
static void vop_crtc_cancel_pending_vblank(struct drm_crtc *crtc,
struct drm_file *file_priv)
{
struct drm_device *drm = crtc->dev;
struct vop *vop = to_vop(crtc);
struct drm_pending_vblank_event *e;
unsigned long flags;
spin_lock_irqsave(&drm->event_lock, flags);
e = vop->event;
if (e && e->base.file_priv == file_priv) {
vop->event = NULL;
e->base.destroy(&e->base);
file_priv->event_space += sizeof(e->event);
}
spin_unlock_irqrestore(&drm->event_lock, flags);
}
static const struct rockchip_crtc_funcs private_crtc_funcs = {
.enable_vblank = vop_crtc_enable_vblank,
.disable_vblank = vop_crtc_disable_vblank,
.wait_for_update = vop_crtc_wait_for_update,
.cancel_pending_vblank = vop_crtc_cancel_pending_vblank,
};
static bool vop_crtc_mode_fixup(struct drm_crtc *crtc,