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....@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?
Then, adv7511_cec_irq_process() will have less chance to be called from
adv7511_irq_process() (assuming CONFIG_DRM_I2C_ADV7511_CEC is defined)
if adv7511->i2c_main->irq is zero.
But, anyway, it seems that commit f3d9683346d6 ("drm/bridge: adv7511:
Allow IRQ to share GPIO pins") is even more broken to handle the CEC case,
as adv7511_cec_adap_enable() may enable some interrupts for CEC.
This is a bit complicated. Thoughts?
Regards,
Liu Ying
