Comment 13 for bug 1370707

Seeing the same in Trusty 14.04 LTS with kernel 3.16. I am now at 3.16.0-34 and still see the same behavior. Every fix I have tried fails to make it work as it did work in as late as 3.14 kernels, and did work in all the 3.13 series. I think that the problem is kernel configuration in the 3.16 kernels. I do not know about 3.15 kernels as none of those I attempted to use would boot my system properly at all.

I have yet to build my own 3.16 kernels to try to track this down but I have noticed that one of the differences between the 3.13 and 3.14 series kernels, and the 3.16 series kernels, is that CONFIG_DRM_RADEON_UMS is commented out in 3.16 kernels, but not in either 3.13 or 3.14 series kernels from Ubuntu (at least not the ones I used, and I have not been building too many of my own kernels this LTS release, as that kind of defeats the purpose of an LTS release).

I am using a Radeon HD 5750 card with dual, Dell S2440L monitors.

Any further information needed, let me know. I am going to attempt to use apport to send up my configuration, and so forth, in a couple minutes. Last time I tried it failed in another bug.