[PATCH] Add option to use DPI calculated from EDID

Michal Suchanek hramrach at centrum.cz
Tue Oct 11 13:02:28 PDT 2011

On 11 October 2011 20:20, Matt Dew <marcoz at osource.org> wrote:
> On 10/11/2011 11:25 AM, Alex Deucher wrote:
>> On Tue, Oct 11, 2011 at 1:16 PM, Michal Suchanek<hramrach at centrum.cz>
>>  wrote:
>>> Hello,
>>> this is a patch that fixes a long-standing issue with the X server.
>>> The X server discards EDID information and sets DPI always to 96.
>>> This is a regression since 1.7 introduced in fff00d .
>>> There is no option to use the information obtained from EDID.
>> What happens if you have two or three monitors attached with wildly
>> different DPIs?
> Is it required that all monitors are set to the same DPI?

Note that DPI is reported for screen as a whole so there is only one
DPI for any number of monitors you have unless you analyze XRandR
information of each output separately.

AFAIK no application does use XRandR for DPI (which reports EDID
information regardless of this option) so far.

The best you can hope for is correct results for one-screen setup and
semi-correct for setups that have screen of similar DPI.

Still there is no reason to force the X server report wrong DPI for
setups that would work flawlessly like high-DPI screens on small

If your setup is not handled by this option then you probably need to
update whatever toolkit you use to use xrandr.



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