On Thu, 26 Mar 2015, Tvrtko Ursulin <tvrtko.ursu...@linux.intel.com> wrote: > On 03/26/2015 01:30 PM, Ville Syrjälä wrote: >> On Thu, Mar 26, 2015 at 12:39:40PM +0000, Tvrtko Ursulin wrote: >>> From: Tvrtko Ursulin <tvrtko.ursu...@intel.com> >>> >>> intel_user_framebuffer_destroy() requires the struct_mutex for its >>> object bookkeeping, so this means that all calls to >>> drm_framebuffer_unreference must be held without that lock. >>> >>> This is a simplified version of the identically named patch by Chris Wilson. >>> >>> References: https://bugs.freedesktop.org/show_bug.cgi?id=89166 >>> Cc: Chris Wilson <ch...@chris-wilson.co.uk> >>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursu...@intel.com> >>> --- >>> drivers/gpu/drm/i915/intel_display.c | 10 ++++++++++ >>> 1 file changed, 10 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/i915/intel_display.c >>> b/drivers/gpu/drm/i915/intel_display.c >>> index cb50854..0788507 100644 >>> --- a/drivers/gpu/drm/i915/intel_display.c >>> +++ b/drivers/gpu/drm/i915/intel_display.c >>> @@ -14020,11 +14020,21 @@ void intel_modeset_gem_init(struct drm_device >>> *dev) >>> c->primary->fb, >>> c->primary->state, >>> NULL)) { >>> + /* >>> + * We must drop struct_mutex when calling >>> + * drm_framebuffer_unreference and it is safe to do so >>> + * because it is not needed at this point anyway. >>> + * At this stage the driver is still single-threaded and >>> + * we are taking it only to silence a warning in >>> + * intel_pin_and_fence_fb_obj. >>> + */ >>> + mutex_unlock(&dev->struct_mutex); >>> DRM_ERROR("failed to pin boot fb on pipe %d\n", >>> to_intel_crtc(c)->pipe); >>> drm_framebuffer_unreference(c->primary->fb); >>> c->primary->fb = NULL; >>> update_state_fb(c->primary); >>> + mutex_lock(&dev->struct_mutex); >>> } >>> } >>> mutex_unlock(&dev->struct_mutex); >> >> Just grab the mutex around the pin_and_fence inside the loop. It doesn't >> protect anything else. > > Well the comment says so, but this way it only grabs and releases it > once if there are multiple active crtcs and nothing fails. So I was > hoping the comment was enough to explain the reality, even though the > other option would be more obvious code strictly speaking.
Tvrtko & Ville, can you reach a solution on this one? Or is there a new patch that I may have missed? BR, Jani. > > Regards, > > Tvrtko > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx
