linux-kernel - Re: [PATCH 09/19] drm/radeon: handle lockup in delayed work, v2

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Message-ID: <53DF9C88.6060107@amd.com>
Date:	Mon, 4 Aug 2014 16:45:28 +0200
From:	Christian König <christian.koenig@....com>
To:	Maarten Lankhorst <maarten.lankhorst@...onical.com>,
	<airlied@...ux.ie>
CC:	<thellstrom@...are.com>, <nouveau@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
	<bskeggs@...hat.com>, <alexander.deucher@....com>
Subject: Re: [PATCH 09/19] drm/radeon: handle lockup in delayed work, v2

Am 04.08.2014 um 16:40 schrieb Maarten Lankhorst:
> op 04-08-14 16:37, Christian König schreef:
>>> It'a pain to deal with gpu reset.
>> Yeah, well that's nothing new.
>>
>>> I've now tried other solutions but that would mean reverting to the old style during gpu lockup recovery, and only running the delayed work when !lockup.
>>> But this meant that the timeout was useless to add. I think the cleanest is keeping the v2 patch, because potentially any waiting code can be called during lockup recovery.
>> The lockup code itself should never call any waiting code and V2 doesn't seem to handle a couple of cases correctly either.
>>
>> How about moving the fence waiting out of the reset code?
> What cases did I miss then?
>
> I'm curious how you want to move the fence waiting out of reset, when there are so many places that could potentially wait, like radeon_ib_get can call radeon_sa_bo_new which can do a wait, or radeon_ring_alloc that can wait on radeon_fence_wait_next, etc.

The IB test itself doesn't needs to be protected by the exclusive lock. 
Only everything between radeon_save_bios_scratch_regs and 
radeon_ring_restore.

Christian.
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