On 28.05.2015 22:21, Yogi A. Patel wrote: > > Setup - I am using a custom-compiled Linux kernel 3.14.17 on Ubuntu > 14.04. The kernel is patched with Xenomai using Ipipe > 3.14.17-x84-4.patch. I have a Radeon HD 8570HD R7 240 graphics card in > this system. > > I can confirm that the radeon driver is compiled and loaded, and by > running “sudo lshw -C Display”, I can verify that my graphics card is > using the Radeon driver. > > Problem - Now, when I run the latency test in Xenomai, I obtain large > latencies - up to 40us. If I blacklist the radeon, drm, drm_kms_help, > ttm, i2c_algo_bit kernel modules, and run the latency test with gdm not > running, the latencies are under 10us. > > In previous kernel versions, such as 3.8.13, I have never seen such big > differences in latency results between gdm running/not running.
Can you narrow down when the problem was introduced in the kernel, ideally with git bisect? Assuming DPM is enabled, have you tried disabling that with radeon.dpm=0 on the kernel command line? Please attach the dmesg output pertaining to drm/radeon. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ xorg-driver-ati mailing list [email protected] http://lists.x.org/mailman/listinfo/xorg-driver-ati
