linux-kernel - Re: [PATCH 1/2] PNPACPI: cope with invalid device IDs

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Message-Id: <201009171656.11239.bjorn.helgaas@hp.com>
Date:	Fri, 17 Sep 2010 16:56:08 -0600
From:	Bjorn Helgaas <bjorn.helgaas@...com>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	Len Brown <lenb@...nel.org>, linux-kernel@...r.kernel.org,
	linux-acpi@...r.kernel.org, Matthew Garrett <mjg59@...f.ucam.org>
Subject: Re: [PATCH 1/2] PNPACPI: cope with invalid device IDs

On Friday, September 17, 2010 04:49:39 pm Dmitry Torokhov wrote:
> On Friday, September 17, 2010 03:37:31 pm Bjorn Helgaas wrote:
> > On Friday, June 04, 2010 08:24:04 pm Dmitry Torokhov wrote:
> > > If primary ID (HID) is invalid try locating first valid ID on compatible
> > > ID list before giving up.
> > > 
> > > This helps, for example, to recognize i8042 AUX port on Sony Vaio VPCZ1
> > > which uses SNYSYN0003 as HID. Without the patch users are forced to
> > > boot with i8042.nopnp to make use of their touchpads.
> > 
> > Sorry, we seem to have dropped the ball on this.  Looking at it again,
> > 
> > I have another question below:
> > >  drivers/pnp/pnpacpi/core.c |   29 ++++++++++++++++++++++++-----
> > >  1 files changed, 24 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
> > > index f7ff628..2029cb5 100644
> > > --- a/drivers/pnp/pnpacpi/core.c
> > > +++ b/drivers/pnp/pnpacpi/core.c
> > > @@ -28,7 +28,7 @@
> > > 
> > >  #include "../base.h"
> > >  #include "pnpacpi.h"
> > > 
> > > -static int num = 0;
> > > +static int num;
> > > 
> > >  /* We need only to blacklist devices that have already an acpi driver
> > >  that
> > >  
> > >   * can't use pnp layer. We don't need to blacklist device that are
> > >   directly
> > > 
> > > @@ -157,11 +157,24 @@ struct pnp_protocol pnpacpi_protocol = {
> > > 
> > >  };
> > >  EXPORT_SYMBOL(pnpacpi_protocol);
> > > 
> > > +static char *pnpacpi_get_id(struct acpi_device *device)
> > > +{
> > > +	struct acpi_hardware_id *id;
> > > +
> > > +	list_for_each_entry(id, &device->pnp.ids, list) {
> > > +		if (ispnpidacpi(id->id))
> > > +			return id->id;
> > > +	}
> > > +
> > > +	return NULL;
> > > +}
> > > +
> > > 
> > >  static int __init pnpacpi_add_device(struct acpi_device *device)
> > >  {
> > >  
> > >  	acpi_handle temp = NULL;
> > >  	acpi_status status;
> > >  	struct pnp_dev *dev;
> > > 
> > > +	char *pnpid;
> > > 
> > >  	struct acpi_hardware_id *id;
> > >  	
> > >  	/*
> > > 
> > > @@ -169,11 +182,17 @@ static int __init pnpacpi_add_device(struct
> > > acpi_device *device)
> > > 
> > >  	 * driver should not be loaded.
> > >  	 */
> > >  	
> > >  	status = acpi_get_handle(device->handle, "_CRS", &temp);
> > > 
> > > -	if (ACPI_FAILURE(status) || !ispnpidacpi(acpi_device_hid(device)) ||
> > > -	    is_exclusive_device(device) || (!device->status.present))
> > > +	if (ACPI_FAILURE(status))
> > > +		return 0;
> > > +
> > > +	pnpid = pnpacpi_get_id(device);
> > > +	if (!pnpid)
> > > +		return 0;
> > > +
> > > +	if (!is_exclusive_device(device) || !device->status.present)
> > > 
> > >  		return 0;
> > 
> > Doesn't this change the sense of the is_exclusive_device() test?
> 
> Yes, it does, "!" shoudl be dropped.
> 
> OTOH maybe we should keep the "primary" ID as is (so SYNSYN0003 would
> still be _the_ id) but only refuse device if none of it's IDs (neither
> _HID nor _CID) satisfy ispnpidacpi() requirements.

I think we *should* keep the entire SYNSYN0003 ID, but I don't think
we currently can because we use a fixed-length array to store it.
I haven't had time or motivation to fix that yet.

Do you want to post an update fixing the is_exclusive_device() thing?

Bjorn
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