linux-kernel - Re: [alsa-devel] PNP_DRIVER_RES_DISABLE breaks swsusp at least with snd

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Date:	Thu, 10 Jan 2008 02:53:06 +0100
From:	Rene Herman <rene.herman@...access.nl>
To:	Ondrej Zary <linux@...nbow-software.org>
CC:	Linux Kernel <linux-kernel@...r.kernel.org>,
	alsa-devel@...a-project.org, Jaroslav Kysela <perex@...e.cz>,
	Bjorn Helgaas <bjorn.helgaas@...com>
Subject: Re: [alsa-devel] PNP_DRIVER_RES_DISABLE breaks swsusp at least with
 snd_cs4236

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?

> The same .flags value is present in many of the ALSA ISA sound drivers.
> 
> Removing that .flags line caused this to appear inlog when loading snd_cs4236 
> module:
> CS4236+ WSS PnP manual resources are invalid, using auto config
> CS4236+ CTRL PnP manual resources are invalid, using auto config
> CS4236+ MPU401 PnP manual resources are invalid, using auto config
> 
> and the sound now works after resume!
> 
> So the question is: why is this line present?
> 
> Is this a bug? What's the correct fix?

Rene.

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