From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Andrzej Hajda <a.hajda@samsung.com>
Cc: grant.likely@secretlab.ca, linux-samsung-soc@vger.kernel.org,
dri-devel@lists.freedesktop.org,
Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Subject: Re: [PATCH] drm/exynos: resolve infinite loop issue on non multi-platform
Date: Fri, 7 Nov 2014 08:27:04 -0800 [thread overview]
Message-ID: <20141107162704.GC10256@kroah.com> (raw)
In-Reply-To: <545CA8DC.3070400@samsung.com>
On Fri, Nov 07, 2014 at 12:11:24PM +0100, Andrzej Hajda wrote:
> On 11/06/2014 06:08 PM, Sjoerd Simons wrote:
> > On Thu, 2014-11-06 at 23:10 +0900, Inki Dae wrote:
> >> This patch resovles the infinite loop issue incurred
> >> when Exyno drm driver is enabled but all kms drivers
> >> are disabled on Exynos board by returning -EPROBE_DEFER
> >> only in case that there is kms device registered.
> >
> > It would be nice if you could explain in the commit message/comment why
> > returning -EPROBE_DEFER causes an infinite loop and why it's the wrong
> > thing to do in this case?
> >
> > Even if you know this probe will never succeed in the future (so
> > deferring is actually pointless), deferring really shouldn't trigger
> > infinte loops in calling code
> >
>
> +CC: Grant and Greg
>
> It seems to be partly an issue with deferred probing. I guess it affects
> all drivers which in their probe can cause successful probe of
> sub-driver/sub-device, and after that the main driver defers probing,
> unwinding changes including removal of sub-driver/sub-device. Driver
> core incorrectly re-triggers probing in this case.
>
> In this particular case it could be fixed in exynos_drm driver I guess,
> but maybe it would be good to fix deferred probing, if possible.
Patches are always gladly accepted :)
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next prev parent reply other threads:[~2014-11-07 16:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-06 14:10 [PATCH] drm/exynos: resolve infinite loop issue on non multi-platform Inki Dae
2014-11-06 15:44 ` Emil Velikov
2014-11-06 15:46 ` Emil Velikov
2014-11-06 17:08 ` Sjoerd Simons
2014-11-07 11:11 ` Andrzej Hajda
2014-11-07 16:27 ` Greg Kroah-Hartman [this message]
2014-11-07 8:29 ` Andrzej Hajda
2014-11-07 11:27 ` Inki Dae
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