Re: [alsa-devel] PNP_DRIVER_RES_DISABLE breaks swsusp at least withsnd_cs4236

From: Rene Herman
Date: Wed Jan 09 2008 - 20:56:25 EST


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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