diff options
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/drm_fb_helper.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 0aac5450c8ad..4b8119510687 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -398,16 +398,32 @@ static int drm_fb_helper_damage_blit(struct drm_fb_helper *fb_helper, struct dma_buf_map map, dst; int ret; + /* + * We have to pin the client buffer to its current location while + * flushing the shadow buffer. In the general case, concurrent + * modesetting operations could try to move the buffer and would + * fail. The modeset has to be serialized by acquiring the reservation + * object of the underlying BO here. + * + * For fbdev emulation, we only have to protect against fbdev modeset + * operations. Nothing else will involve the client buffer's BO. So it + * is sufficient to acquire struct drm_fb_helper.lock here. + */ + mutex_lock(&fb_helper->lock); + ret = drm_client_buffer_vmap(buffer, &map); if (ret) - return ret; + goto out; dst = map; drm_fb_helper_damage_blit_real(fb_helper, clip, &dst); drm_client_buffer_vunmap(buffer); - return 0; +out: + mutex_unlock(&fb_helper->lock); + + return ret; } static void drm_fb_helper_damage_work(struct work_struct *work) |