[Intel-gfx] [PATCH] sna: CustomEDID fix

[Chris Wilson]

Quoting dom.constant at free.fr (2018-02-06 18:57:05)
> 
> 
> > Quoting dom.constant at free.fr (2018-02-02 18:37:12)
> > > Hello,
> > > 
> > > For my HTPC setup, I'm using the option "CustomEDID".
> > > With this option, output attaching and destroying events leads to
> > > crashes.
> > > 
> > > The following sequence leads to a crash:
> > > - In xorg.conf: Option "CustomEDID" "HDMI2:/etc/my_edid.bin"
> > > - Starting Xorg
> > > - Connect HDMI2
> > > - Disconnect HDMI2
> > > - Reconnect HDMI2
> > >   -> Crash
> > > 
> > > 
> > > The crash happens in xf86OutputSetEDID
> > > (xorg/xserver/hw/xfree86/modes/xf86Crtc.c)
> > > at "free(output->MonInfo)". MonInfo is assigned with
> > > sna_output->fake_edid_mon
> > > which is allocated by intel driver in sna_output_load_fake_edid
> > > (src/sna/sna_display.c).
> > > 
> > > 
> > > Sequence details:
> > > - Starting Xorg
> > >    -> fake_edid_mon is initialized
> > > 
> > > - Connect HDMI2
> > >    -> xf86OutputSetEDID is called:
> > >        - MonInfo is NULL
> > >        - MonInfo is assigned with fake_edid_mon pointer
> > >        - MonInfo is read by Xorg
> > > 
> > > - Disconnect HDMI2
> > > 
> > > - Reconnect HDMI2
> > >    -> xf86OutputSetEDID is called:
> > >        - MonInfo is freed thus also fake_edid_mon
> > >        - MonInfo is assigned with fake_edid_mon
> > >        - MonInfo is read but it was freed -> CRASH
> > > 
> > > 
> > > The fix consists of a new instance of xf86MonPtr for each calls of
> > > xf86OutputSetEDID.
> > > This instance is initialized with fake_edid_raw which render
> > > fake_edid_mon useless.
> > > With this proposal, the behaviour of an EDID override is similar to
> > > a "real" EDID.
> > > 
> > > Regards,
> > > 
> > > 
> > > Signed-off-by: Dominique Constant <dom.constant at free.fr>
> > > To: Chris Wilson <chris at chris-wilson.co.uk>
> > 
> > Apologies if this is a resend, but could you send me this patch using
> > "git send-email" (or attach the output of "git format-patch"). git am
> > is not happy with it.
> > -Chris
> > 
> 
> 
> Hello,
> Thank you for taking into consideration this patch.

Finally, got around to picking up patches for -intel. Thank you very
much for the fix,
-Chris