[radeon r100] when ring test fails, provide users with option to test

[Christian König]

On 02.12.2015 04:14, Michel Dänzer wrote:
> On 01.12.2015 19:01, Pavel Machek wrote:
>> On Mon 2015-11-30 09:39:54, Christian König wrote:
>>> On 29.11.2015 23:22, Pavel Machek wrote:
>>>> On Sun 2015-11-29 20:48:53, Christian König wrote:
>>>>> On 28.11.2015 21:58, Pavel Machek wrote:
>>>>>> Ring test failure is often caused by too high agpmode. Tell the user
>>>>>> what to try.
>>>>>>
>>>>>> Signed-off-by: Pavel Machek <pavel at ucw.cz>
>>>>> NAK, the ring test can fail for any number of reasons and the agpmode is
>>>>> actually rather unlikely to be the cause.
>>>> Well, when I asked on the list "why this is happened" I got "umm,
>>>> noone knows" response that was not exactly helpful. And then someone
>>>> told me about agpmode.
>>>>
>>>> If you know about the reasons it can fail, could you list them near
>>>> the DRM_ERROR, at least as a comment?
>>> Well as I said, that could be any number of reasons. Some of them even
>>> completely unrelated to the driver itself.
>>>
>>> E.g. BIOS setting, faulty hardware, problems with the writeback etc... There
>>> is really not a list you could give here.
>>>
>>> Lowering the agpmode usually helps more to prevent random corruptions and
>>> problems under load.
>> Take a look at
>>
>> http://www.gossamer-threads.com/lists/linux/kernel/2197183
>>
>> . I had a problem, you did not know how to debug it, but it already
>> happened to pebolle at tiscali ... and yes, it was agpmode. That
>> problem is clearly more common then you realize... So this should go
>> in.
> I agree with Christian, but at the very least, agpmode must not be
> mentioned if AGP isn't being used in the first place, i.e. either the
> GPU isn't AGP or is being forced to PCI(e) mode.

Well maybe to explain the background, r100_ring_test() is used for a 
whole bunch of different hardware generations.

Most of them doesn't even have AGP, so mentioning this here would be 
even confusion for the majority of users.

Regards,
Christian.