[Intel-gfx] [PATCH] drm/i915: Update ring space correctly on lrc context reset

[Mika Kuoppala]

Jani Nikula <jani.nikula at linux.intel.com> writes:

> On Wed, 02 Sep 2015, Arun Siluvery <arun.siluvery at linux.intel.com> wrote:
>> On 20/08/2015 16:27, Chris Wilson wrote:
>>> On Thu, Aug 20, 2015 at 05:34:59PM +0300, Mika Kuoppala wrote:
>>>> If we leave the last_retired_head to pre-reset value, we might
>>>> end up in a situation where intel_ring_space() returns wrong
>>>> value on next hardware init.
>>>
>>> http://patchwork.freedesktop.org/patch/46612/
>>> and earlier
>>> -Chris
>>>
>> Hi Chris,
>>
>> I see the warning even with below batch,
>>
>> [Intel-gfx] [PATCH 50/70] drm/i915: The argument for postfix is redundant
>> http://patchwork.freedesktop.org/patch/46601/
>>
>> the following patch need to be updated as it uses olr,
>> [Intel-gfx] [PATCH 51/70] drm/i915: Record the position of the start of 
>> the request
>> http://patchwork.freedesktop.org/patch/46612/
>>
>> Do we need some of the previous patches in series as well?
>>
>> This patch is fixing the issue in the current code, do you think we can 
>> get this in its current state?
>
> Is this patch still valid?
>

My understanding is that Chris wants more throughout
revamp of the code so that we have a common ringbuffer init.
And then go further and remove the special reset handling in
execlist case.

But argument for this patch is that it fixes a bug in current
nightly and it makes the legacy ring init and execlist ring init
identical how they set/reset the ring space. Until we gain
the generic ringbuffer init code.

Chris?

-Mika

> BR,
> Jani.
>
>
> -- 
> Jani Nikula, Intel Open Source Technology Center