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SubjectRe: [alsa-devel] PNP_DRIVER_RES_DISABLE breaks swsusp at least with snd_cs4236
On Thu, 10 Jan 2008, Rene Herman wrote:

> On 09-01-08 23:43, Ondrej Zary wrote:
>
> Jaroslav -- in your role as ISA-PnP maintainer and Bjorn, in yours as
> having been foollish enough to touch PnP recently:
>
> > as hibernation (swsusp) started to work with my CPU, I found that my Turtle
> > Beach Malibu stops working after resume from hibernation. It's caused by fact
> > that the card is not enabled on the pnp layer during resume - and thus card
> > registers are inaccessible (reads return FFs, writes go nowhere).
> >
> > During resume, pnp_bus_resume() in drivers/pnp/driver.c is called for each pnp
> > device. This function calls pnp_start_dev() only when the
> > PNP_DRIVER_RES_DO_NOT_CHANGE bit is NOT seting pnp_drv->flags. But the cs4236
> > driver in sound/isa/cs423x/cs4236.c explicitly sets the .flags to
> > PNP_DRIVER_RES_DISABLE - it's value is 3 and that includes
> > PNP_DRIVER_RES_DO_NOT_CHANGE bit.
>
> Ehm. Isn't that a bit unexpected:
>
> #define PNP_DRIVER_RES_DO_NOT_CHANGE 0x0001 /* do not change the state
> of the device */
> #define PNP_DRIVER_RES_DISABLE 0x0003 /* ensure the device is
> disabled */
>
> I'd say that disabling is changing, so isn't this just a braino where
> someone meant to write 2 instead of 3?

It's irrelevant. I think that condition in driver.c in suspend and resume
callbacks is invalid, because PNP_DRIVER_RES_DO_NOT_CHANGE means that
resources should not be changed in the pnp core but only in the driver,
but in suspend/resume process are resources preserved, so the condition
should be removed.

Author of this code is:

author Pierre Ossman <drzeus-list@drzeus.cx> Tue, 29 Nov 2005 09:09:32 +0100
committer Jaroslav Kysela <perex@suse.cz> Tue, 03 Jan 2006 12:31:30 +0100

[ALSA] [PATCH] alsa: Improved PnP suspend support

Also use the PnP functions to start/stop the devices during the suspend so
that drivers will not have to duplicate this code.

Cc: Adam Belay <ambx1@neo.rr.com>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>


Jaroslav

-----
Jaroslav Kysela <perex@perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.



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