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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, Mar 23, 2017 at 09:47:47PM +0100, Wolfram Sang wrote:
> On Fri, Mar 10, 2017 at 04:58:35PM +0300, Viktor Krasnov wrote:
> 
> Thanks for the patch!
> 
> adding linux-acpi to CC. This is more an ACPI question than I2C.

Mika? Andy? Jarkko? Any input on this?

> 
> > From: Edgar Cherkasov <echerkasov@xxxxxxxxxxxxx>
> > 
> > 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.
> > 
> > Signed-off-by: Edgar Cherkasov <echerkasov@xxxxxxxxxxxxx>
> > Signed-off-by: Michael Brunner <Michael.Brunner@xxxxxxxxxxx>
> > Acked-by: Viktor Krasnov <vkrasnov@xxxxxxxxxxxxx>
> > ---
> >  drivers/i2c/busses/i2c-scmi.c | 1 +
> >  include/acpi/acpi_drivers.h   | 2 ++
> >  2 files changed, 3 insertions(+)
> > 
> > diff --git a/drivers/i2c/busses/i2c-scmi.c b/drivers/i2c/busses/i2c-scmi.c
> > index dfc98df..fb9aee0 100644
> > --- a/drivers/i2c/busses/i2c-scmi.c
> > +++ b/drivers/i2c/busses/i2c-scmi.c
> > @@ -51,6 +51,7 @@ struct acpi_smbus_cmi {
> >  static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
> >  	{"SMBUS01", (kernel_ulong_t)&smbus_methods},
> >  	{ACPI_SMBUS_IBM_HID, (kernel_ulong_t)&ibm_smbus_methods},
> > +	{ACPI_SMBUS_MS_HID, (kernel_ulong_t)&smbus_methods},
> >  	{"", 0}
> >  };
> >  MODULE_DEVICE_TABLE(acpi, acpi_smbus_cmi_ids);
> > diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
> > index 29c6912..d34538b 100644
> > --- a/include/acpi/acpi_drivers.h
> > +++ b/include/acpi/acpi_drivers.h
> > @@ -60,6 +60,8 @@
> >  #define ACPI_DOCK_HID			"LNXDOCK"
> >  /* Quirk for broken IBM BIOSes */
> >  #define ACPI_SMBUS_IBM_HID		"SMBUSIBM"
> > +/* SMBUS HID definition as supported by Microsoft Windows */
> > +#define ACPI_SMBUS_MS_HID		"SMB0001"
> >  
> >  /*
> >   * For fixed hardware buttons, we fabricate acpi_devices with HID
> > -- 
> > 1.9.3
> > 


Attachment: signature.asc
Description: PGP signature


[Index of Archives]     [Linux GPIO]     [Linux SPI]     [Linux Hardward Monitoring]     [LM Sensors]     [Linux USB Devel]     [Linux Media]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux