Subject: Re: [radeon r100] when ring test fails, provide users with option to
 test
To: Pavel Machek <pavel@ucw.cz>
References: <20151128205840.GA26757@amd> <565B56A5.4080702@amd.com>
 <20151129222235.GA25692@amd>
CC: Trivial patch monkey <trivial@kernel.org>, <alexander.deucher@amd.com>,
        <airlied@linux.ie>, <dri-devel@lists.freedesktop.org>,
        <linux-kernel@vger.kernel.org>
From: =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>
Message-ID: <565C0B5A.2040103@amd.com>
Date: Mon, 30 Nov 2015 09:39:54 +0100
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On 29.11.2015 23:22, Pavel Machek wrote:
> On Sun 2015-11-29 20:48:53, Christian K?nig 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@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.

Regards,
Christian.

>
> Thanks,
> 									Pavel
>
>> Regards,
>> Christian.
>>
>>> diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
>>> index 238b13f..32b1917 100644
>>> --- a/drivers/gpu/drm/radeon/r100.c
>>> +++ b/drivers/gpu/drm/radeon/r100.c
>>> @@ -3665,7 +3665,7 @@ int r100_ring_test(struct radeon_device *rdev, struct radeon_ring *ring)
>>>   	if (i < rdev->usec_timeout) {
>>>   		DRM_INFO("ring test succeeded in %d usecs\n", i);
>>>   	} else {
>>> -		DRM_ERROR("radeon: ring test failed (scratch(0x%04X)=0x%08X)\n",
>>> +		DRM_ERROR("radeon: ring test failed (scratch(0x%04X)=0x%08X), try radeon.agpmode=1?\n",
>>>   			  scratch, tmp);
>>>   		r = -EINVAL;
>>>   	}
>>>

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