Re: [PATCHv3] drm: adv7511/33: Fix adv7511_cec_init() failure handling

From: John Stultz <john.stultz@linaro.org>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Arnd Bergmann <arnd@arndb.de>, David Airlie <airlied@linux.ie>,
	lkml <linux-kernel@vger.kernel.org>,
	dri-devel@lists.freedesktop.org,
	Hans Verkuil <hans.verkuil@cisco.com>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Bhumika Goyal <bhumirks@gmail.com>
Subject: Re: [PATCHv3] drm: adv7511/33: Fix adv7511_cec_init() failure handling
Date: Wed, 22 Nov 2017 16:22:59 -0800	[thread overview]
Message-ID: <CALAqxLVoOPrAG242y5iyaXUiavAo0PVG7zze14ruXJH6U6vVSw@mail.gmail.com> (raw)
In-Reply-To: <9097b2a4-b6b9-5fca-e039-0a17694b1143@xs4all.nl>

On Tue, Nov 21, 2017 at 12:17 AM, Hans Verkuil <hverkuil@xs4all.nl> wrote:
> If the device tree for a board did not specify a cec clock, then
> adv7511_cec_init would return an error, which would cause adv7511_probe()
> to fail and thus there is no HDMI output.
>
> There is no need to have adv7511_probe() fail if the CEC initialization
> fails, so just change adv7511_cec_init() to a void function. In addition,
> adv7511_cec_init() should just return silently if the cec clock isn't
> found and show a message for any other errors.
>
> An otherwise correct cleanup patch from Dan Carpenter turned this broken
> failure handling into a kernel Oops, so bisection points to commit
> 7af35b0addbc ("drm/kirin: Checking for IS_ERR() instead of NULL") rather
> than 3b1b975003e4 ("drm: adv7511/33: add HDMI CEC support").
>
> Based on earlier patches from Arnd and John.
>
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Cc: Xinliang Liu <xinliang.liu@linaro.org>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Cc: Sean Paul <seanpaul@chromium.org>
> Cc: Archit Taneja <architt@codeaurora.org>
> Cc: John Stultz <john.stultz@linaro.org>
> Link: https://bugs.linaro.org/show_bug.cgi?id=3345
> Link: https://lkft.validation.linaro.org/scheduler/job/48017#L3551
> Fixes: 7af35b0addbc ("drm/kirin: Checking for IS_ERR() instead of NULL")
> Fixes: 3b1b975003e4 ("drm: adv7511/33: add HDMI CEC support")
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> Tested-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
> This rework of Arnd and John's patches goes a bit further and just silently
> exits if there is no cec clock defined in the dts. I'm sure that's the
> reason why the kirin board failed on this. BTW: if the kirin board DOES
> support cec, then it would be nice if it can be hooked up in the dts!
>
> Tested with my Dragonboard and Renesas Koelsch board. Also tested what
> happens when probing is deferred due to missing cec clock.
>
> John, can you test this again?

Sorry I didn't get back to you yesterday on this!

Seems to be working ok for me!

Tested-by: John Stultz <john.stultz@linaro.org>

thanks!
-john