Re: [alsa-devel] [PATCH] ASoC: intel: Fix crash at suspend/resume after failed codec registration
From: Pierre-Louis Bossart
Date: Mon Mar 25 2019 - 09:18:09 EST
On 3/25/19 8:12 AM, Mark Brown wrote:
On Sat, Mar 23, 2019 at 09:55:46AM -0400, Pierre-Louis Bossart wrote:
I'd like to highlight that there is a fundamental flaw in the way the
machine drivers are handled. Since we don't have a hook for the machine
driver in the BIOS, the DSP driver creates a platform_device which will
instantiate the machine driver. When errors happen in the machine driver
probe, they are suppressed due to a 'feature' of the device model, so you
can end-up with a broken configuration that is still reported as a
successful strobe.
These are driver specific issues not device model issues as far as I can
see? The issue fixed by this as is that you're storing a pointer in the
ASoC level (not device model level) probe that you don't free when the
component is unbound, causing you to dereference it later during
suspend. There is absolutely no problem with the machine driver not
being guaranteed to bind at the time it's initially registered, that's
perfectly normal and should cause no problems.
Agree, what I was referring is that if the machine probe and card
registration fails (not just deferred), the parent acpi/pci driver isn't
notified - there is just no means to provide that information and that
leads to all kinds of configuration issues.