On 2013.09.08 at 17:32 -0700, Eric W. Biederman wrote: > Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx> writes: > > > Here are a couple of patches that get kexec working with radeon devices. > > I've tested this on my RS780. > > Comments or flames are welcome. > > Thanks. > > A couple of high level comments. > > This looks promising for the usual case. > > Removing the printk at the end of the kexec path seems a little dubious, > what of other cpus, interrupt handlers, etc. Basically estabilishing a > new rule on when printk is allowed seems a little dubious at this point, > even if it is a useful debugging trick. OK. I will drop this patch. It doesn't seem to be necessary, because I cannot reproduce the printk related hang anymore. > Having a clean shutdown of the radeon definitely seems worth doing, > because the cases where we care abouty video are when a person is in > front of the system. Yes. But please note that even with radeon_pci_shutdown implemented, I still get ring test failures on roughly every eighth kexec boot: [drm:r600_dma_ring_test] *ERROR* radeon: ring 3 test failed (0xCAFEDEAD) radeon 0000:01:05.0: disabling GPU acceleration That's definitely better than the current state of affairs, with ring test failures on every second boot. But I haven't figured out the reason for these failures yet. It's curious that once a ring test failure occurs, it will reliably fail after each kexec invocation, no matter how often repeated. Only a reboot brings the machine back to normal. > I don't know if you want to remove the sanity checks. They seem cheap > and safe regardless. Are they expensive or ineffective? Moreover if > they work a reasonable amount of the time that means that the kexec on > panic case (where we don't shut anything down) can actually use the > video, and that in general the driver will be more robust. I don't > expect anyone much cares as kexec on panic is mostly used to just write > a core file to the network, or the local disk. But if it is easy to > keep that case working most of the time, why not. IIRC Alex said the sanity checks are expensive and boot-time could be improved by dropping them. Maybe he can chime in? -- Markus _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
