[Skiboot] [PATCH skiboot] npu2: Clear fence on all bricks

[Alexey Kardashevskiy]

Ping?


On 02/12/2019 13:05, Alexey Kardashevskiy wrote:
> 
> 
> On 30/11/2019 03:47, Reza Arbab wrote:
>> On Fri, Nov 22, 2019 at 11:04:22AM +1100, Alexey Kardashevskiy wrote:
>>> Reza/Ryan, could you please add more details about what exactly causes
>>> these UR HMIs? Thanks!
>>
>> Hopefully I've pieced together the bug history correctly. As I
>> understand it...
>>
>> Each GPU has a 640kb protected region which will result in a
>> "unsupported request" (UR) response. The root bug is that the driver
>> maps and accidentally accesses that area.
> 
> Oh. Is this address range described anywhere? We could disable mapping
> these as a precaution measure.
> 
> 
>> This firmware patch helps for recovery. From our perspective it may seem
>> redundant to clear the fence on all bricks instead of just the one we're
>> resettting, but at a hardware level the above UR sends a fence signal to
>> all the hardware units so they all need to be cleared.
>>
>> Acked-by: Reza Arbab <arbab at linux.ibm.com>
> 
> 
> Thanks!
> 
> 

-- 
Alexey