[PATCH] Revert "drm/radeon: Try evicting from CPU accessible to inaccessible VRAM first"

[Christian König]

Am 29.03.2017 um 10:59 schrieb Michel Dänzer:
> On 28/03/17 08:00 PM, Julien Isorce wrote:
>> On 28 March 2017 at 10:36, Michel Dänzer <michel at daenzer.net
>> <mailto:michel at daenzer.net>> wrote:
>>
>>      On 28/03/17 05:24 PM, Julien Isorce wrote:
>>      > Hi Michel,
>>      >
>>      > About the hard lockup, I noticed that I cannot have it with the
>>      > following conditions:
>>      >
>>      > 1. soft lockup fix (the 0->i change which avoids infinite loop)
>>      > 2. Your suggestion: (!(rbo->flags & RADEON_GEM_CPU_ACCESS)
>>      > 3. radeon.gartsize=512 radeon.vramlimit=1024 (any other values above do
>>      > not help, for example (1024, 1024) or (1024, 2048))
>>      >
>>      > Without 1 and 2, but with 3, our test reproduces the soft lockup (just
>>      > discovered few days ago).
>>      > Without 3 (and with or without 1., 2.), our test reproduces the hard
>>      > lockup which one does not give any info in kern.log (sometimes some NUL
>>      > ^@ characters but not always).
>>
>>      What exactly does "hard lockup" mean? What are the symptoms?
>>
>>
>> Screens are frozen, cannot ssh, no mouse/keyboard, no kernel panic.
>> Requires hard reboot.
>> After reboot, nothing in /var/crash, nothing in /sys/fs/pstore, nothing
>> in kern.log except sometimes some nul characters ^@.
> Does it still respond to ping when it's hung?
>
>
>> Using a serial console did not show additional debug messages. kgdb was
>> not useful but probably worth another attempt.
> Right.
>
> Anyway, I'm afraid it sounds like it's probably not directly related to
> the issue I was thinking of for my previous test patch or other similar
> ones I was thinking of writing.

Yeah, agree.

Additional to that a complete crash where you don't even get anything 
over serial console is rather unlikely to be cause by something an 
application can do directly.

Possible causes are more likely power management or completely messing 
up a bus system. Have you tried disabling dpm as well?

Christian.