* Modesetting lock changes breaks vmwgfx since 3.18-rc1 @ 2014-10-30 14:41 Thomas Hellstrom 2014-10-31 17:33 ` Daniel Vetter 0 siblings, 1 reply; 4+ messages in thread From: Thomas Hellstrom @ 2014-10-30 14:41 UTC (permalink / raw) To: Daniel Vetter, dri-devel@lists.freedesktop.org Hi! Details in https://bugzilla.redhat.com/show_bug.cgi?id=1155825 Can whoever broke the driver please make an effort to fix it up? Daniel, You've been named as a suspect. I'm not sure if that is true. Thanks, Thomas _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Modesetting lock changes breaks vmwgfx since 3.18-rc1 2014-10-30 14:41 Modesetting lock changes breaks vmwgfx since 3.18-rc1 Thomas Hellstrom @ 2014-10-31 17:33 ` Daniel Vetter 2014-11-03 10:29 ` Thomas Hellstrom 0 siblings, 1 reply; 4+ messages in thread From: Daniel Vetter @ 2014-10-31 17:33 UTC (permalink / raw) To: Thomas Hellstrom; +Cc: Daniel Vetter, dri-devel@lists.freedesktop.org On Thu, Oct 30, 2014 at 03:41:31PM +0100, Thomas Hellstrom wrote: > Hi! > > Details in > > https://bugzilla.redhat.com/show_bug.cgi?id=1155825 > > Can whoever broke the driver please make an effort to fix it up? > > Daniel, You've been named as a suspect. I'm not sure if that is true. Yeah the recent locking frobbing didn't account for the FIXME comment in vmwgfx. Might be good to address that long-term to get vmwgfx more in line with everyone else again - I simply don't understand the interactions well enough to make that call. There's two of those in total. Can we just remove them perhaps? The question is whether you can do the cursor operation just with the per-crtc lock as protection, or whether there's any shared resources and you need the full exclusion provided by modeset_lock_all. If the crtc locking is good enough then we could rip this out in both function and be done. Note that this FIXME has been in vmwgfx since almost two years now. If that's not possible then I have a major kludge of a hack in my atomic helpers branch which will keep this alive for a bit longer. It ain't pretty though. Cheers, Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Modesetting lock changes breaks vmwgfx since 3.18-rc1 2014-10-31 17:33 ` Daniel Vetter @ 2014-11-03 10:29 ` Thomas Hellstrom 2014-11-03 16:10 ` Daniel Vetter 0 siblings, 1 reply; 4+ messages in thread From: Thomas Hellstrom @ 2014-11-03 10:29 UTC (permalink / raw) To: Daniel Vetter; +Cc: Daniel Vetter, dri-devel@lists.freedesktop.org Hi! On 10/31/2014 06:33 PM, Daniel Vetter wrote: > On Thu, Oct 30, 2014 at 03:41:31PM +0100, Thomas Hellstrom wrote: >> Hi! >> >> Details in >> >> https://urldefense.proofpoint.com/v2/url?u=https-3A__bugzilla.redhat.com_show-5Fbug.cgi-3Fid-3D1155825&d=AAIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=lsrU5TbpNlecpBoc0CpsmwopYh2VrihduvgGEIFPsXw&s=uzLKWffads4edz_fJN5-3K2IObzmVFUcH6kty4ObySs&e= >> >> Can whoever broke the driver please make an effort to fix it up? >> >> Daniel, You've been named as a suspect. I'm not sure if that is true. > Yeah the recent locking frobbing didn't account for the FIXME comment in > vmwgfx. Might be good to address that long-term to get vmwgfx more in line > with everyone else again - I simply don't understand the interactions well > enough to make that call. There's two of those in total. > > Can we just remove them perhaps? The question is whether you can do the > cursor operation just with the per-crtc lock as protection, or whether > there's any shared resources and you need the full exclusion provided by > modeset_lock_all. If the crtc locking is good enough then we could rip > this out in both function and be done. > > Note that this FIXME has been in vmwgfx since almost two years now. > > If that's not possible then I have a major kludge of a hack in my atomic > helpers branch which will keep this alive for a bit longer. It ain't > pretty though. > > Cheers, Daniel Hi. Actually we haven't looked much at the new modesetting locking at all but been pretty happy with what others have put in the code, but it sounds like we need to actually deal with this now. I've basically never been really convinced that we'd see any modesetting locking contention with a single lock, but OTOH I guess with a single lock we'd eventually start to run into locking recursion problems. /Thomas _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Modesetting lock changes breaks vmwgfx since 3.18-rc1 2014-11-03 10:29 ` Thomas Hellstrom @ 2014-11-03 16:10 ` Daniel Vetter 0 siblings, 0 replies; 4+ messages in thread From: Daniel Vetter @ 2014-11-03 16:10 UTC (permalink / raw) To: Thomas Hellstrom; +Cc: Daniel Vetter, dri-devel@lists.freedesktop.org On Mon, Nov 03, 2014 at 11:29:39AM +0100, Thomas Hellstrom wrote: > Hi! > > On 10/31/2014 06:33 PM, Daniel Vetter wrote: > > On Thu, Oct 30, 2014 at 03:41:31PM +0100, Thomas Hellstrom wrote: > >> Hi! > >> > >> Details in > >> > >> https://urldefense.proofpoint.com/v2/url?u=https-3A__bugzilla.redhat.com_show-5Fbug.cgi-3Fid-3D1155825&d=AAIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=lsrU5TbpNlecpBoc0CpsmwopYh2VrihduvgGEIFPsXw&s=uzLKWffads4edz_fJN5-3K2IObzmVFUcH6kty4ObySs&e= > >> > >> Can whoever broke the driver please make an effort to fix it up? > >> > >> Daniel, You've been named as a suspect. I'm not sure if that is true. > > Yeah the recent locking frobbing didn't account for the FIXME comment in > > vmwgfx. Might be good to address that long-term to get vmwgfx more in line > > with everyone else again - I simply don't understand the interactions well > > enough to make that call. There's two of those in total. > > > > Can we just remove them perhaps? The question is whether you can do the > > cursor operation just with the per-crtc lock as protection, or whether > > there's any shared resources and you need the full exclusion provided by > > modeset_lock_all. If the crtc locking is good enough then we could rip > > this out in both function and be done. > > > > Note that this FIXME has been in vmwgfx since almost two years now. > > > > If that's not possible then I have a major kludge of a hack in my atomic > > helpers branch which will keep this alive for a bit longer. It ain't > > pretty though. > > > > Cheers, Daniel > > Hi. > > Actually we haven't looked much at the new modesetting locking at all > but been pretty happy with what others have put in the code, but it > sounds like we need to actually deal with this now. I've basically never > been really convinced that we'd see any modesetting locking contention > with a single lock, but OTOH I guess with a single lock we'd eventually > start to run into locking recursion problems. The problem only happens on real hardware, where you need to read EDIDs in the background and other probe fun. At glance that means we'll just have 2 locks, one fore probe stuff and one for everything else. Except for nasty overlapping cases, which require the entire thing to be pretty ridiculously flexible ;-) But on virtual hardware where no kms op takes a long time fine-grained locking is indeed complete overkill. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-11-03 16:10 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-10-30 14:41 Modesetting lock changes breaks vmwgfx since 3.18-rc1 Thomas Hellstrom 2014-10-31 17:33 ` Daniel Vetter 2014-11-03 10:29 ` Thomas Hellstrom 2014-11-03 16:10 ` Daniel Vetter
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