Re: [PATCH v2] i2c: i2c-scmi: add a MS HID

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Wed, Apr 05, 2017 at 02:59:32PM +0200, Jean Delvare wrote:
> On Tue,  4 Apr 2017 19:18:27 +0300, Viktor Krasnov wrote:
> > From: Edgar Cherkasov <echerkasov@dev.rtsoft.ru>
> > 
> > Description of the problem:
> >  - i2c-scmi driver contains only two identifiers "SMBUS01" and "SMBUSIBM";
> >  - the fist HID (SMBUS01) is clearly defined in "SMBus Control Method
> >    Interface Specification, version 1.0": "Each device must specify
> >    'SMBUS01' as its _HID and use a unique _UID value";
> >  - unfortunately, BIOS vendors (like AMI) seem to ignore this requirement
> >    and implement "SMB0001" HID instead of "SMBUS01";
> >  - I speculate that they do this because only "SMB0001" is hard coded in
> >    Windows SMBus driver produced by Microsoft.
> > 
> > This leads to following situation:
> >  - SMBus works out of box in Windows but not in Linux;
> >  - board vendors are forced to add correct "SMBUS01" HID to BIOS to make
> >    SMBus work in Linux. Moreover the same board vendors complain that
> >    tools (3-rd party ASL compiler) do not like the "SMBUS01" identifier
> >    and produce errors.  So they need to constantly patch the compiler for
> >    each new version of BIOS.
> > 
> > As it is very unlikely that BIOS vendors implement a correct HID in
> > future, I would propose to consider whether it is possible to work around
> > the problem by adding MS HID to the Linux i2c-scmi driver.
> > 
> > v2: move the definition of the new HID to the driver itself.
> > 
> > Signed-off-by: Edgar Cherkasov <echerkasov@dev.rtsoft.ru>
> > Signed-off-by: Michael Brunner <Michael.Brunner@kontron.com>
> > Acked-by: Viktor Krasnov <vkrasnov@dev.rtsoft.ru>
> 
> Reviewed-by: Jean Delvare <jdelvare@suse.de>

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>