[PATCH xserver] edid: Prune duplicates after adding modes from DDC

[Chen, Xiaogang]

> -----Original Message-----
> From: Michel Dänzer [mailto:michel at daenzer.net]
> Sent: Thursday, February 23, 2017 7:05 PM
> To: Chen, Xiaogang <Xiaogang.Chen at amd.com>; xorg-devel at lists.x.org
> Cc: jorge_monteagudo at hotmail.com
> Subject: Re: [PATCH xserver] edid: Prune duplicates after adding modes from
> DDC
> 
> On 23/02/17 06:46 AM, Chen, Xiaogang wrote:
> >> From: Michel Dänzer [mailto:michel at daenzer.net]
> >>
> >> Multiple calls to xf86EdidMonitorSet (which can be triggered e.g. by
> >> running
> >> xrandr) would potentially keep adding the same modes, causing the
> >> Monitor-
> >>> Modes list to keep growing larger and using up more memory.
> >>
> >> Fix this by calling xf86PruneDuplicateModes after adding the modes
> >> returned by xf86DDCGetModes. This removes any newly added modes
> which
> >> were already in the Monitor->Modes list before, but keeps new modes
> >> which weren't yet.
> >>
> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99521
> >> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
> >> ---
> >>
> >> Xiaogang / Jorge, does this fix the memory leak you're seeing?
> >>
> > [XCHEN] Hi Michel: I tested your patch with same script I used before
> > (while true; do xrandr --verbose; done), the memory leak is still there.
> > Actually the xf86PruneDuplicateModes() is called before at
> > xf86DDCGetModes() which is called by xf86EdidMonitorSet().
> 
> xf86DDCGetModes only calls xf86PruneDuplicateModes for the list of modes it
> generates itself (note that xf86DDCGetModes isn't called only by
> xf86EdidMonitorSet). The xf86PruneDuplicateModes call added by my patch
> works on the combined Monitor->Modes list with the modes returned by
> xf86DDCGetModes appended. The question now is why that call doesn't
> actually eliminate the duplicate modes.
> 
> 
> > I think the point here is: why we need to have these "mode"? I do not
> > find these "mode" got used afterword.
> 
> grep the tree for '->Modes'.
[XCHEN] Those modes(generated by xf86DDCGetModes )are added at (xf86OutputPtr)output->scrn->monitor->modes. I searched the reference for it from the source tree, did not see those modes get freed. 
It not seems mode duplicating issue, those modes need to be freed.

> 
> 
> --
> Earthling Michel Dänzer               |               http://www.amd.com
> Libre software enthusiast             |             Mesa and X developer