[PATCH 00/14] drm: Make DRM's IRQ helpers legacy

Thomas Zimmermann tzimmermann at suse.de
Wed Jul 28 05:19:17 UTC 2021

Hi Sam

Am 27.07.21 um 20:51 schrieb Sam Ravnborg:
> Hi Thomas,
> On Tue, Jul 27, 2021 at 08:27:07PM +0200, Thomas Zimmermann wrote:
>> DRM's IRQ helpers are only helpful for old, non-KMS drivers. Move
>> the code behind CONFIG_DRM_LEGACY. Convert KMS drivers to Linux
>> IRQ interfaces.
>> DRM provides IRQ helpers for setting up, receiving and removing IRQ
>> handlers. It's an abstraction over plain Linux functions. The code
>> is mid-layerish with several callbacks to hook into the rsp drivers.
>> Old UMS driver have their interrupts enabled via ioctl, so these
>> abstractions makes some sense. Modern KMS manage all their interrupts
>> internally. Using the DRM helpers adds indirection without benefits.
>> Most KMs drivers already use Linux IRQ functions instead of DRM's
>> abstraction layer. Patches 1 to 12 convert the remaining ones.
>> The patches also resolve a bug for devices without assigned interrupt
>> number. DRM helpers don't test for IRQ_NOTCONNECTED, so drivers do
>> not detect if the device has no interrupt assigned.
> Before diving into a review of these..
> Any specific reason devm_request_irq is not used?

Thanks for looking at the patches.

Switching to devm_ definately makes sense in the longer term.
  I didn't do this here to not change the order of clean-up operations 
in general. And some of the drivers have dedicated IRQ clean-up code, 
which might depend on the correct order as well.

Best regards

> 	Sam

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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