https://bugzilla.kernel.org/show_bug.cgi?id=42716
Summary: Boot failure with KMS enabled (radeon) Product: Drivers Version: 2.5 Kernel Version: 3.2.x Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) AssignedTo: drivers_video-dri@kernel-bugs.osdl.org ReportedBy: rw@rlworkman.net Regression: No
Since 3.2.0, my machine [1] fails to boot - it crashes/panics in early boot when the radeon module (or one of its deps) is loaded. Graphics chip is as follows:
VGA compatible controller: ATI Technologies Inc RS690 [Radeon X1200 Series]
This is all running on libdrm-2.4.29, mesa-7.11.2, xorg-server-1.11.4, and xf86-video-ati-6.14.3 with udev-180 (though the problem existed on 178 and 179 as well).
3.2.0, 3.2.1, and now 3.2.2 all exhibit this problem, but 3.1.x (including 3.1.10, which I'm currently using) is fine. If I disable KMS (radeon.modeset=0), then the system boots fine.
I thought I'd be clever and bisect this, so I built about twelve or thirteen kernels, and bisect blamed this commit: [50b8d257486a45cba7b65ca978986ed216bbcc10] ptrace: partially fix the do_wait(WEXITED) vs EXIT_DEAD->EXIT_ZOMBIE race
That doesn't seem reasonable, but sure, it's worth a try. I reversed that patch in mainline 3.2.2, and I get a good boot. However, I notice that this is in /var/log/syslog: Feb 1 21:00:40 isotope kernel: [ 2.039197] [drm:r100_ring_test] *ERROR* radeon: ring test failed (scratch(0x15E4)=0xCAFEDEAD) Feb 1 21:00:40 isotope kernel: [ 2.039256] [drm:r100_cp_init] *ERROR* radeon: cp isn't working (-22). Feb 1 21:00:40 isotope kernel: [ 2.162916] [drm:r100_cp_fini] *ERROR* Wait for CP idle timeout, shutting down CP.
I then booted the vanilla 3.2.2, and it booted just fine. Okay, that's odd, so let's try the patched (reversed bisect patch from above) again. This time, appeared to OOPS after switching over to KMS, but the display is still visible. All of the potentially useful stuff scrolled off the screen, and now there's a constant repetition of the following two lines (with alternating values of CONNECTOR between 17 and 18) flooding the console every few seconds, so I can't pageup back to the OOPS/trace/whatever:
[drm:radeon_atombios_connected_scratch_regs], DFP3 disconnected [drm:output_poll_execute], [CONNECTOR:18:DVI-D-1] status updated from 2 to 2
So, let's reboot to that kernel a few times. #1: all is fine #2: crash/panic after kms load; no video at all #3: crash/panic after kms load; no video at all
This isn't going well, so let's boot the patched kernel again: #1: all is fine #2: all is fine #3: crash/panic after kms load; no video at all
Any idea what's going on here? I don't have the option to attach a serial console, for what that's worth, so that aside, any suggestions for further debugging?