Received-SPF: pass (google.com: domain of linux-kernel+bounces-183646-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Message-ID: <e2d4e8b4-bab4-448f-8b67-21f2902fdcd2@linux.dev>
Date: Mon, 20 May 2024 19:11:10 +0800
Precedence: bulk
MIME-Version: 1.0
Subject: Re: [PATCH] drm/bridge: adv7511: Exit interrupt handling when
 necessary
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
 Liu Ying <victor.liu@nxp.com>
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
 andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org,
 Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se,
 jernej.skrabec@gmail.com, maarten.lankhorst@linux.intel.com,
 mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, daniel@ffwll.ch,
 biju.das.jz@bp.renesas.com, u.kleine-koenig@pengutronix.de,
 aford173@gmail.com, jani.nikula@intel.com, bli@bang-olufsen.dk
References: <20240516101006.2388767-1-victor.liu@nxp.com>
 <evnxopqt5be56vxuxqdj4l3mcd5nrrvucio7jhwgg4emraai3t@gherubdynyip>
Content-Language: en-US, en-AU
From: Sui Jingfeng <sui.jingfeng@linux.dev>
In-Reply-To: <evnxopqt5be56vxuxqdj4l3mcd5nrrvucio7jhwgg4emraai3t@gherubdynyip>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

Hi,

On 5/20/24 06:11, Dmitry Baryshkov wrote:
> On Thu, May 16, 2024 at 06:10:06PM +0800, Liu Ying wrote:
>> Commit f3d9683346d6 ("drm/bridge: adv7511: Allow IRQ to share GPIO pins")
>> fails to consider the case where adv7511->i2c_main->irq is zero, i.e.,
>> no interrupt requested at all.
>>
>> Without interrupt, adv7511_wait_for_edid() could return -EIO sometimes,
>> because it polls adv7511->edid_read flag by calling adv7511_irq_process()
>> a few times, but adv7511_irq_process() happens to refuse to handle
>> interrupt by returning -ENODATA.  Hence, EDID retrieval fails randomly.
>>
>> Fix the issue by checking adv7511->i2c_main->irq before exiting interrupt
>> handling from adv7511_irq_process().
>>
>> Fixes: f3d9683346d6 ("drm/bridge: adv7511: Allow IRQ to share GPIO pins")
>> Signed-off-by: Liu Ying <victor.liu@nxp.com>
>> ---
>>   drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> index 6089b0bb9321..2074fa3c1b7b 100644
>> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> @@ -479,7 +479,8 @@ static int adv7511_irq_process(struct adv7511 *adv7511, bool process_hpd)
>>   		return ret;
>>   
>>   	/* If there is no IRQ to handle, exit indicating no IRQ data */
>> -	if (!(irq0 & (ADV7511_INT0_HPD | ADV7511_INT0_EDID_READY)) &&
>> +	if (adv7511->i2c_main->irq &&
>> +	    !(irq0 & (ADV7511_INT0_HPD | ADV7511_INT0_EDID_READY)) &&
>>   	    !(irq1 & ADV7511_INT1_DDC_ERROR))
>>   		return -ENODATA;
> 
> I think it might be better to handle -ENODATA in adv7511_wait_for_edid()
> instead. WDYT?
> 

I think this is may deserve another patch.

-- 
Best regards
Sui