<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW --- - haswell UXA corruption when unblanking from "xset dpms force off"" href="https://bugs.freedesktop.org/show_bug.cgi?id=71588#c8">Comment # 8</a> on <a class="bz_bug_link bz_status_NEW " title="NEW --- - haswell UXA corruption when unblanking from "xset dpms force off"" href="https://bugs.freedesktop.org/show_bug.cgi?id=71588">bug 71588</a> from <a class="email" href="mailto:rstrode@redhat.com" title="Ray Strode [halfline] <rstrode@redhat.com>"> Ray Strode [halfline]</a> <pre> irc log: <halfline> hey, ryanlerch just grabbed me to show me a weird graphics corruption bug in the gnome-shell lock screen <halfline> after some finagling we figured out the problem happens when a monitor is dpms off'd and comes back <halfline> if he does xset dpms force off then when he comes back the screen contents are stale and or partially corrupted <halfline> maybe it's showing the backbuffer ? not 100% sure <halfline> this is with UXA <halfline> does that ring any bells for you guys? <halfline> problem notably doesn't happen with SNA or the modesetting ddx <marcheu> halfline: framebuffer compression? <halfline> marcheu: are you asking if fbc is enabled ? <marcheu> halfline: yeah, I had a bug like that with bad interaction between fbc and blitter (which is only used in UXA) <marcheu> halfline: if so, bwidawsk send patches to fix it <marcheu> a month ago maybe? <marcheu> s/send/sent <halfline> marcheu: ah interesting, let me walk over and try forcefully disabling it <halfline> and see if that fixes the issue --- ryanlerch is now known as halfryan <halfryan> marcheu, booting with i915.i915_enable_fbc=0 doesn't fix the issue <halfryan> it happens on two haswell machines <marcheu> oh well :) --- halfryan is now known as ryanlerch <halfline> bwidawsk: any insight ? <bwidawsk> halfline: image <halfline> are you asking for a screenshot? sometimes it looks corrupted like this: <a href="http://i.imgur.com/6KPm4Gm.jpg">http://i.imgur.com/6KPm4Gm.jpg</a> with the screen contents offset <halfline> bwidawsk: but sometimes it looks perfectly fine, just "stale" <bwidawsk> can we disable stolen garbage? <bwidawsk> jbarnes: ? <bwidawsk> halfline: can you paste the contents of i915_gem_gtt in debugfs <halfline> bwidawsk: like if we run a command, in the terminal to xset dpms force off, we'll see the command on screen for a brief second before the monitors turn off <halfline> but when they come back on the screen contents will show the terminal before the command was typed <halfline> bwidawsk: after triggering the problem ? <halfline> yea one sec, let me walk back over <ryanlerch> bwidawsk, <a href="http://paste.fedoraproject.org/53828/38437139/">http://paste.fedoraproject.org/53828/38437139/</a> <bwidawsk> ryanlerch: i don't see an easy way to disable stolen, but that's what my gut is telling me is screwed up <ryanlerch> one more copy of the file on a different machine, while the corruption is in progress: <a href="http://ur1.ca/g141g">http://ur1.ca/g141g</a> <ryanlerch> bwidawsk, what is "stolen" ? <ryanlerch> ^ that was halfline on my behalf <bwidawsk> just some special memory which has extra odds of being corrupted <halfline> bwidawsk: and do textures get migrated to this memory when the monitor is dpms off'd ? <bwidawsk> halfline: no <bwidawsk> but when things go off is when things like to write to stolen <bwidawsk> jbarnes, ickle: any simple way to disable stolen use <halfline> ah so theory is, stolen is being used for scan out <halfline> and then when the monitor goes off other things try to use it too <halfline> when it comes back on, it then scans out the junk <anholt> I would object to merging it to 10 <stereotype441> I agree. The informal rule is "only bug fixes get cherry-picked to stable", and adhering to that rule is one of our best tools for ensuring that stable really is stable. <jbarnes> bwidawsk, halfline: maybe PSR? <halfline> jbarnes: want me to try booting with i915.powersave=0 ? <jbarnes> halfline: maybe ping vivijim, he's our PSR expert <jbarnes> if your panel has PSR that could definitely be the issue <jbarnes> not sure if it's tested with UXA <halfline> jbarnes: what's the best way to test that? <halfline> psr = panel self refresh ? <jbarnes> halfline: right <jbarnes> lemme see <bwidawsk> just curious, why did we implicate psr? <jbarnes> halfline: i915_enable_psr <jbarnes> bwidawsk, halfline: just guessing <jbarnes> sounds like fbc or psr corruption --- ryanlerch is now known as halfryan <jbarnes> bwidawsk: not sure about the stolen theory, what's your thinking there? <halfryan> jbarnes: i don't see i915_enable_psr in modinfo output for i915 <bwidawsk> jbarnes: it's just it's offset 0 which is corrupted <bwidawsk> and it looks like not pixel data <bwidawsk> the kernel is too old to tell me which one is currently being scanned out <bwidawsk> but I'd guess it's the one at stolen 0 <halfryan> jbarnes, did the more granular option get added later, and powersave will do the same (+ more) ? <jbarnes> halfryan: yeah maybe it's too new <halfryan> okay will try rebooting with i915.powersave=0 then <jbarnes> bwidawsk: nothing should mess with stolen just with dpms off though <jbarnes> I mean, BIOS-wise anyway <jbarnes> there could definitely be some stray write hitting there <jbarnes> that would make sense <ryanlerch> jbarnes, so i915.powersave=0 does not fix it <ryanlerch> but maybe it's not rolled into that option? <jbarnes> ryanlerch: well if you don't have the psr option I don't think psr is to blame <ryanlerch> okay <jbarnes> so we're back to thinking it's a clobber of some kind <ryanlerch> i do soee i915_sr_status says "self-refresh: enabled" <jbarnes> though really I'd just run sna :) <ryanlerch> not sure if that's related <jbarnes> ickle should probably just remove UXA by now <ryanlerch> i think ajax tried to switch fedora to SNA by default and hit some issues and had to change it back <jbarnes> lost to the mists of time though, at least for me <ajax> i got complained at, anyway. --- ryanlerch is now known as halfryan <halfryan> (woops this is halfline typing) <jbarnes> halfryan: have you filed a bug yet? <halfryan> have not <jbarnes> can you collect what you know so far with camera pics and file a new one? <halfryan> certainly</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>