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Bug#384450: xserver-xorg-core fails to start with "invalid io allocation"



Hi David,

I installed a Radeon 9200SE video card, which I know should work with the free drivers in Debian, and I just discovered that I have the same problem that is described in bug #384450.

I didn't see the bug report at first, because the "invalid io allocation" warning also showed up with the vesa driver, but that driver still worked. Also, the mga driver had worked in the past, so I thought I was experiencing a radeon driver-specific problem that was unrelated to that message. To make things worse, the radeon driver (unlike the nvidia driver in the bug report) doesn't tell you "Resource conflicts detected"; It just quits silently, so I ended up spending a lot of time just trying to find out what the problem was.

I just spent about 15 hours independently coming up with a patch for what I later discovered was this bug, only to find out---just before I was going to submit the patch to the BTS---that the bug is already described in bug #384450, and that the solution (which is almost character-by-character identical to my patch) has been sitting in Bugzilla for at least 3 weeks since the bug was first reported here. You can imagine my frustration.

I'll try to explain the bug, and its implications, here:

The bug is that the Xorg PCI drivers fail to properly decode the I/O port ranges for any PCI cards (not just video cards) having I/O ports that have start or end+1 addresses that aren't 16-byte aligned. In this case, X thought my IDE card had I/O ports that overlapped with those of the video card.[2]

Theoretically, it might be possible for this bug to cause data corruption if the drivers fail to detect a real I/O conflict, or if they try to send output to random I/O ports as a result of incorrectly decoding the port addresses.

Practically-speaking, the result is that adding unrelated, otherwise perfectly Linux-compatible hardware can make accelerated X completely non-functional. For that reason, I think the bug's severity should be upgraded to serious, so that this bug doesn't end up in etch, but I don't want to get into a severity-change war over it.

Would you please consider uploading a new xorg-server package with this patch applied? The patch[1] is trivial to apply: You just stuff it into xorg-server's debian/patches directory, and add it to the debian/patches/series file with the "-p0" flag.

Regards,
- Dwayne


[1] https://bugs.freedesktop.org/attachment.cgi?id=5044
[2] X figured every I/O port from 0x00001058 to 0x4008105f (!) was taken by the IDE card.

--
Dwayne C.  Litzenberger <dlitz@dlitz.net>



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