On Tue, 25 Jul 2023 12:29:07 +0200, Maarten Lankhorst wrote:
Hey,
On 2023-07-24 13:32, Pierre-Louis Bossart wrote:
On 7/19/23 18:41, Maarten Lankhorst wrote:
This was only used to allow modprobing i915, by converting to the -EPROBE_DEFER mechanism, it can be completely removed, and is in fact counterproductive since -EPROBE_DEFER otherwise won't be handled correctly.
I personally remember only that the request_module("i915") was the main motivation for the use of the workqueue, but when it comes to the HDaudio codec management we don't even know what we don't know.
I am a bit worried that the snd-hda-intel driver keeps the workqueue for HDaudio codec initialization, and this patch removes the workqueue completely for SOF. That doesn't seem right. Either both drivers need a workqueue or none need a workqueue.
Maybe what we need is to move the i915/xe initialization out of the workqueue, and see in a second pass if that workqueue can be safely removed from the SOF driver?
As I mentioned in some of the other sound driver conversions. I believe it's possible to completely kill off most workqueues.
However, I don´t have the hardware or knowledge to test it. I saw that the SOF had the non-workqueue path already, so it felt less risky to simply convert it to always use that path.
avs/skylake drivers should be easy to convert too. This is why I left the comment: "Removing the workqueue would simplify init even further, but is left as exercise for the reviewer."
HDA-intel has this retry-probe logic used on AMD's, which makes me more hesitant to convert it.
Yes, HDA-Intel requires either a workqueue or async firmware-loader callback because there is some codec module-autoload mechanism that may happen during the probe phase. It's not only on AMD, but it's required in general for all codecs.
Takashi