While investigating rare Xserver (errno=22 in select) and X client (losing X connection) crashes that seem to be related to the new linux-core drm I found this in savage_dri.c and several other DDX drivers:
...driverSwapMethod = DRI_HIDE_X_CONTEXT;
This seems to indicate that the Xserver is somehow involved in direct rendering buffer swap operations and the driver-independent DRI code installs a DRM signal handler for it. I changed it to DRI_KERNEL_SWAP in the savage driver and have not got any crashes since. I'm going to stress this system a bit more tomorrow. GL apps still work, as expected since in the savage driver the kernel is currently not involved in buffer swaps. It's all done client side.
This is all to do with the original drm design providing a number of different ways to implement context switching. All the "modern" drivers use one, I believe that it was DRI_HIDE_X_CONTEXT, though the names are quite confusing. Basically there were provisions to allow context switches to be handled in the kernel, in the 3d driver or in the X server.
I think the reason that you are experiencing failures is because the X server is trying to read or poll the drm filehandle, but Jon has recently changed the behaviour of that filehandle to return an error on those operations, rather than indicating that no bytes are pending.
Let me stress that in most drivers there is no need for the X server to be looking at this filehandle at all, but the code which does so is widely distributed and this change to the DRM will break it.
Keith
------------------------------------------------------- This SF.net email is sponsored by: IT Product Guide on ITManagersJournal Use IT products in your business? Tell us what you think of them. Give us Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more http://productguide.itmanagersjournal.com/guidepromo.tmpl -- _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
