From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH] i2c: i2c-scmi: add a MS HID Date: Fri, 24 Mar 2017 10:16:05 +0100 Message-ID: <20170324101605.7a2c8893@endymion> References: <1489154315-26499-1-git-send-email-vkrasnov@dev.rtsoft.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:51477 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934874AbdCXJQJ (ORCPT ); Fri, 24 Mar 2017 05:16:09 -0400 In-Reply-To: <1489154315-26499-1-git-send-email-vkrasnov@dev.rtsoft.ru> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Viktor Krasnov Cc: wsa@the-dreams.de, linux-i2c@vger.kernel.org, Edgar Cherkasov , Michael Brunner On Fri, 10 Mar 2017 16:58:35 +0300, Viktor Krasnov wrote: > From: Edgar Cherkasov > > 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 > Signed-off-by: Michael Brunner > Acked-by: Viktor Krasnov > --- > 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 No objection from me. Reviewed-by: Jean Delvare -- Jean Delvare SUSE L3 Support