linux-kernel - Re: [PATCH v2] drm: Add the new api to install irq

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Date:   Tue, 3 Nov 2020 11:10:27 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     Maxime Ripard <maxime@...no.tech>,
        Tian Tao <tiantao6@...ilicon.com>
Cc:     maarten.lankhorst@...ux.intel.com, airlied@...ux.ie,
        daniel@...ll.ch, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm: Add the new api to install irq

Hi

Am 03.11.20 um 10:52 schrieb Maxime Ripard:
> On Tue, Nov 03, 2020 at 10:10:41AM +0800, Tian Tao wrote:
>> Add new api devm_drm_irq_install() to register interrupts,
>> no need to call drm_irq_uninstall() when the drm module is removed.
>>
>> v2:
>> fixed the wrong parameter.
>>
>> Signed-off-by: Tian Tao <tiantao6@...ilicon.com>
>> ---
>>  drivers/gpu/drm/drm_drv.c | 23 +++++++++++++++++++++++
>>  include/drm/drm_drv.h     |  3 ++-
>>  2 files changed, 25 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>> index cd162d4..0fe5243 100644
>> --- a/drivers/gpu/drm/drm_drv.c
>> +++ b/drivers/gpu/drm/drm_drv.c
>> @@ -39,6 +39,7 @@
>>  #include <drm/drm_color_mgmt.h>
>>  #include <drm/drm_drv.h>
>>  #include <drm/drm_file.h>
>> +#include <drm/drm_irq.h>
>>  #include <drm/drm_managed.h>
>>  #include <drm/drm_mode_object.h>
>>  #include <drm/drm_print.h>
>> @@ -678,6 +679,28 @@ static int devm_drm_dev_init(struct device *parent,
>>  	return ret;
>>  }
>>  
>> +static void devm_drm_dev_irq_uninstall(void *data)
>> +{
>> +	drm_irq_uninstall(data);
>> +}
>> +
>> +int devm_drm_irq_install(struct device *parent,
>> +			 struct drm_device *dev, int irq)
>> +{
>> +	int ret;
>> +
>> +	ret = drm_irq_install(dev, irq);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = devm_add_action(parent, devm_drm_dev_irq_uninstall, dev);
>> +	if (ret)
>> +		devm_drm_dev_irq_uninstall(dev);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(devm_drm_irq_install);
>> +
> 
> Shouldn't we tie the IRQ to the drm device (so with drmm_add_action)
> instead of tying it to the underlying device?

If the HW device goes away, there won't be any more interrupts. So it's
similar to devm_ functions for I/O memory. Why would you use the drmm_
interface?

Best regards
Thomas

> 
> Maxime
>>

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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