On Thu, Jul 20, 2017 at 03:24:13PM +0100, Russell King - ARM Linux wrote: > On Thu, Jul 20, 2017 at 03:19:10PM +0100, Liviu Dudau wrote: > > On Thu, Jul 20, 2017 at 02:08:29PM +0100, Russell King - ARM Linux wrote: > > > On Thu, Jul 20, 2017 at 01:54:04PM +0100, Liviu Dudau wrote: > > > > On Thu, Jul 20, 2017 at 12:44:49PM +0100, Russell King - ARM Linux wrote: > > > > > Actually, scrub that idea - drm_helper_probe_single_connector_modes() > > > > > calls drm_edid_to_eld() for these cases anyway, so we must call > > > > > drm_helper_probe_single_connector_modes() with the audio_mutex held. > > > > > > > > OK, so the lockdep warning is spurious? > > > > > > I don't think so. I think there's two ways to solve this: > > > > > > 1. replace the audio_mutex in tda998x_audio_get_eld() and > > > tda998x_connector_fill_modes() with a new mutex (eld_mutex) to > > > protect just the ELD. > > > > > > 2. remove the mutex from these two functions, and take the connection_mutex > > > modeset lock in tda998x_audio_get_eld(). > > > > > > However, I don't have a view on which would be best. > > > > If you don't mind, I took the liberty of picking option 2, just because > > I don't like adding new locks when existing ones might do the job. > > I don't mind - but one question for the DRM people in connection with > your patch is whether we need the acquire context for this relatively > simple lock/copy/unlock sequence. This path for getting the ELD > shouldn't be holding any other DRM locks. Cc-ing Daniel Vetter in hope of clarifications / nod of approval. However, I can only see my emails in the online dri-devel archive, not yours, so I can't point him to the whole discussion. danvet: a while ago while I was debugging the delayed fb setup I found a lockdep warning with the tda998x driver. Now I've had some more time to investigate so I have created a patch trying to fix the issue, which was on v1 just a re-ordering of places where tda998x's audio_mutex lock was taken. Russell suggested a different approach, which I have implemented in [1], but we wonder if we really have to go through the whole dance. Best regards, Liviu [1] https://lists.freedesktop.org/archives/dri-devel/2017-July/147940.html > > -- > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up > according to speedtest.net. -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯ _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
