Linux only allows one device driver to attach to a device like the radeon. Right now this driver is radeonfb. When DRM loads it uses the radeon hardware without attaching to it and informing the kernel. What DRM is doing is not compatible with hotplug. DRM enables the framebuffer without reserving it's PCI address. Since the kernel doesn't know about this a hotplug device can get assigned an address on top of the framebuffer. That would cause a hardware conflict and probably result in a reboot.
My solution to this is to make radeon DRM depend on radeonfb. radeonfb properly attaches to the device and marks everything in use. I chose this method because Xegl wants radeonfb loaded and this scheme has minimal code impact. The attached patch is against the current 2.6 kernel source. After applying it loading radeon will also cause radeonfb to be loaded. Note that loading radeonfb does not activate fbconsole. You have to also load the fbconsole module for that. radeonfb should just sit passively in memory and not effect your normal VGA console or DRM. If you are are non-x86 the patch doesn't really do much since you already had radeonfb loaded. [EMAIL PROTECTED] linux-merge]# lsmod Module Size Used by radeonfb 86720 0 i2c_algo_bit 8200 1 radeonfb cfbcopyarea 3840 1 radeonfb radeon 73088 1 radeonfb drm 56084 1 radeon cfbimgblt 2944 1 radeonfb cfbfillrect 3712 1 radeonfb softcursor 1920 1 radeonfb fb 36136 2 radeonfb,softcursor The patch also contains some demo code showing how radeon DRM can remove some duplicated code and use the version in radeonfb. Can everyone please try this patch out and see if loading radeonfb causes any problems on your system. Having radeonfb loaded on x86 is not a normal case. Radeon Xegl is going to depend on having both radeon and radeonfb loaded so I need to know if this will cause problems. For a quicker check you can just do modprobe radeonfb from a console (not a xterm). That will load the current radonfb driver but it will also blank your console font. The blank is from a problem in radeonfb that is fixed in the patch. Type /sbin/setsysfont and the font will be restored and you can then check for any other issues. -- Jon Smirl [EMAIL PROTECTED]
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