dummy driver and maximum resolutions, config hacks via LD_PRELOAD, etc

[Antoine Martin]

On 04/07/2011 06:57 AM, Adam Jackson wrote:
> On 4/6/11 6:38 PM, Aaron Plattner wrote:
>> On Wed, Apr 06, 2011 at 02:37:52PM -0700, Antoine Martin wrote:
>>> diff --git a/src/dummy_driver.c b/src/dummy_driver.c
>>> index 804e41e..05450d5 100644
>>> --- a/src/dummy_driver.c
>>> +++ b/src/dummy_driver.c
>>> @@ -85,6 +85,9 @@ static Bool   dummyDriverFunc(ScrnInfoPtr pScrn,
>>> xorgDriverFuncOp op,
>>>   #define DUMMY_MINOR_VERSION PACKAGE_VERSION_MINOR
>>>   #define DUMMY_PATCHLEVEL PACKAGE_VERSION_PATCHLEVEL
>>>
>>> +#define DUMMY_MAX_WIDTH=4096
>>> +#define DUMMY_MAX_HEIGHT=4096
>>
>> 4096 is low.  Modern GPUs go up to at least 16kx16k, and I think you can
>> get away with X screens at the protocol level up to 32kx32k, though I
>> vaguely recall there being some restriction against that.
>
> It should be 64k-1, but because of protocol bugs (and 4G overflow on
> 32bpp) it ends up being 32k-1.
OK, please find an updated patch attached (using 2^15-1 as maximum size).

There is also a specfile patch for Fedora, RPMs for Fedora 13,14,15 and
rawhide can be found here:
http://winswitch.org/dists/rpm/Fedora/

I have tested it on Fedora 14 quite a bit, are there any specific
validation tests I should be aware of?
I went up to resolutions like these (does use a lot of RAM!):
screen #0:
  dimensions:    16384x8192 pixels (4335x2167 millimeters)
But to test higher than this I would need a modeline calculator that
doesn't overflow (xtiming did):
Modeline "32000x32000 at 0" -38917.43 32000 32032 -115848 -115816 32000
32775 32826 33601



Any chance of seeing a new minor version of dummy tagged?
This would help push this to users sooner rather than later.

Last question: can anyone think of a distro agnostic way of detecting if
the dummy driver has this big-screen support without starting a full
Xorg instance and seeing the result? My software would need to know this
in order to choose between Xvfb and Xorg+dummy.

strings /usr/lib*/xorg/modules/drivers/dummy_drv.so
isn't very clean and doesn't show any version information.

> Also, #define A B, not #define A=B.
Ooops, sorry about that, that's obviously not what I had used for building.

Thanks
Antoine

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: xf86-video-dummy-allowbigscreens.diff
URL: <http://lists.x.org/archives/xorg/attachments/20110407/9eb6445d/attachment.ksh>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: xorg-x11-drv-dummy-allowbigscreens-fedoraspecfile.patch
URL: <http://lists.x.org/archives/xorg/attachments/20110407/9eb6445d/attachment-0001.ksh>