Received-SPF: pass (google.com: domain of linux-kernel+bounces-183284-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Date: Mon, 20 May 2024 01:11:08 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: 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, 
	sui.jingfeng@linux.dev
Subject: Re: [PATCH] drm/bridge: adv7511: Exit interrupt handling when
 necessary
Message-ID: <evnxopqt5be56vxuxqdj4l3mcd5nrrvucio7jhwgg4emraai3t@gherubdynyip>
References: <20240516101006.2388767-1-victor.liu@nxp.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240516101006.2388767-1-victor.liu@nxp.com>

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?

-- 
With best wishes
Dmitry