Re: [PATCH] drm/bridge: adv7511: Exit interrupt handling when necessary

From: Sui Jingfeng
Date: Mon May 20 2024 - 07:11:27 EST


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@xxxxxxx>
---
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