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staging: drm/omap: avoid aquiring mutex in atomic context (v2) 

omap_gem_roll() could be called by fbcon in atomic context or when
struct_mutext is held.  Avoid aquiring mutex (deadlock), or calling
tiler_pin() (which itself is not safe for atomic context) in these
cases.

Signed-off-by: Rob Clark <rob@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
hifive-unleashed-5.1
Rob Clark 2011-12-16 11:34:34 -06:00 committed by Greg Kroah-Hartman
parent 510d4d32f2
commit af69592aa0
1 changed files with 14 additions and 2 deletions
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16
drivers/staging/omapdrm/omap_gem.c
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@ -538,10 +538,22 @@ int omap_gem_roll(struct drm_gem_object *obj, uint32_t roll)
return -EINVAL;
}
mutex_lock(&obj->dev->struct_mutex);
omap_obj->roll = roll;
if (in_atomic() || mutex_is_locked(&obj->dev->struct_mutex)) {
/* this can get called from fbcon in atomic context.. so
* just ignore it and wait for next time called from
* interruptible context to update the PAT.. the result
* may be that user sees wrap-around instead of scrolling
* momentarily on the screen. If we wanted to be fancier
* we could perhaps schedule some workqueue work at this
* point.
*/
return 0;
}
mutex_lock(&obj->dev->struct_mutex);
/* if we aren't mapped yet, we don't need to do anything */
if (omap_obj->block) {
struct page **pages;