Re: [alsa-devel] [PATCH] ALSA: hda: Request driver probe from an async task

On Mon, 23 Apr 2018 14:05:52 +0200, Paul Menzel wrote:

From: Paul Menzel pmenzel@molgen.mpg.de Date: Sat, 24 Mar 2018 09:28:43 +0100

On an ASRock E350M1, with Linux 4.17-rc1 according to `initcall_debug` calling `azx_driver_init` takes sometimes more than a few milliseconds, and up to 200 ms.

[    2.892598] calling  azx_driver_init+0x0/0xfe4 [snd_hda_intel] @ 218
[    2.943002] initcall azx_driver_init+0x0/0xfe4 [snd_hda_intel]
returned 0 after 49195 usecs

Trying to execute the Linux kernel in less than 500 ms, this is quite a hold-up, and therefore request the probe from an async task.

With this change, the test shows, that the function returns earlier.

[    3.254800] calling  azx_driver_init+0x0/0xfe4 [snd_hda_intel] @ 227
[    3.254887] initcall azx_driver_init+0x0/0xfe4 [snd_hda_intel]
returned 0 after 66 usecs

The same behavior is visible on a Dell OptiPlex 7010. The longer times seem to happen, when the module *e1000e* is probed during the same time.

Signed-off-by: Paul Menzel pmenzel@molgen.mpg.de

What actually took so long? Could you analyze further instead of blindly putting the flag?

thanks,

Takashi