linux-kernel - Re: [PATCH 02/12] drm/nouveau/timer: skip calibration on GK20A

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 11 Apr 2014 17:31:17 +1000
From:	Ben Skeggs <skeggsb@...il.com>
To:	Alexandre Courbot <gnurou@...il.com>
Cc:	Thierry Reding <thierry.reding@...il.com>,
	Alexandre Courbot <acourbot@...dia.com>,
	"nouveau@...ts.freedesktop.org" <nouveau@...ts.freedesktop.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	Ben Skeggs <bskeggs@...hat.com>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH 02/12] drm/nouveau/timer: skip calibration on GK20A

On Fri, Apr 11, 2014 at 12:46 PM, Alexandre Courbot <gnurou@...il.com> wrote:
> On Wed, Mar 26, 2014 at 1:19 PM, Ben Skeggs <skeggsb@...il.com> wrote:
>> On Tue, Mar 25, 2014 at 7:54 AM, Thierry Reding
>> <thierry.reding@...il.com> wrote:
>>> On Mon, Mar 24, 2014 at 05:42:24PM +0900, Alexandre Courbot wrote:
>>>> GK20A's timer is directly attached to the system timer and cannot be
>>>> calibrated. Skip the calibration phase on that chip since the
>>>> corresponding registers do not exist.
>>>>
>>>> Signed-off-by: Alexandre Courbot <acourbot@...dia.com>
>>>> ---
>>>>  drivers/gpu/drm/nouveau/core/subdev/timer/nv04.c | 19 +++++++++++++------
>>>>  1 file changed, 13 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/nouveau/core/subdev/timer/nv04.c b/drivers/gpu/drm/nouveau/core/subdev/timer/nv04.c
>>>> index c0bdd10358d7..822fe0d8a871 100644
>>>> --- a/drivers/gpu/drm/nouveau/core/subdev/timer/nv04.c
>>>> +++ b/drivers/gpu/drm/nouveau/core/subdev/timer/nv04.c
>>>> @@ -185,6 +185,10 @@ nv04_timer_init(struct nouveau_object *object)
>>>>       if (ret)
>>>>               return ret;
>>>>
>>>> +     /* gk20a does not have the calibration registers */
>>>> +     if (device->chipset == 0xea)
>>>> +             goto skip_clk_init;
>>>
>>> I'm concerned that this won't scale in the future. Perhaps a better
>>> solution would be to add a "flags" or "features" field to struct
>>> nouveau_device along with feature bits such as HAS_CALIBRATION or
>>> similar.
>>>
>>> That way we don't have to touch this code for every new future Tegra
>>> chip. Unless perhaps if there's a reason to expect things to change in
>>> newer generations.
>> I've already handled this in a slightly different way in the tree I'd
>> previously pointed Alex at (I think!), as I needed to do the same for
>> GM107.
>>
>> Should just be able to use that implementation (so, just change the
>> probe patch) here too.
>
> I will skip this patch and use your implementation then. Btw,
> shouldn't the source file for the GK20A implementation be named nvea.c
> instead of gk20a.c?
For the Maxwell stuff I've been using "gm107" now too.  Since we're
working with you guys these days it seems better to use the same names
for things ;)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/