Hi All, On 3/1/22 22:01, Dmitry Torokhov wrote: > On Tue, Nov 09, 2021 at 11:12:34AM +0200, Andy Shevchenko wrote: >> On Tue, Nov 9, 2021 at 10:11 AM Sachi King <nakato@xxxxxxxxx> wrote: >>> >>> The AMD variant of the Surface Laptop report 0 for their OEM platform >>> revision. The Surface devices that require the surfacepro3_button >>> driver do not have the _DSM that gets the OEM platform revision. If the >>> method does not exist, load surfacepro3_button. >> >> ... >> >>> * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device >>> * ID (MSHW0040) for the power/volume buttons. Make sure this is the right >>> - * device by checking for the _DSM method and OEM Platform Revision. >>> + * device by checking for the _DSM method and OEM Platform Revision DSM >>> + * function. >> >> Not sure what this change means (not a native speaker). >> >> ... >> >>> - dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev); >> >> I think this is useful to have. >> >> What about leaving it as is for debugging purposes and just replacing >> the last test? > > I agree it is nice to be able to print it for debug purposes, but it has > to be fetched separately, as with the proposed change we are not reading > it. > > If I am understanding the change it wants to call acpi_dsm_check() > to verify whether MSHW0040_DSM_GET_OMPR function exists at all (which is > done by reading _DSM MSHW0040_DSM_UUID, revision MSHW0040_DSM_REVISION, > function 0. Only if function 0 indicates that function > MSHW0040_DSM_GET_OMPR is supported in this _DSM, we can read it to get > the real version number, which can be 0. > > Treating 0 as an invalid version as it was done in original change is > wrong. > > I propose we combine the old and new code, call acpi_dsm_check() and > bail if it returns false, otherwise proceed to calling > acpi_evaluate_dsm_typed() and dev_dbg() the version. > > Sachi, are you going to update the patch? You do not need to adjust the > surface driver as Hans is getting rid of it. Right, for more info on that see: https://lore.kernel.org/linux-input/20220224110241.9613-1-hdegoede@xxxxxxxxxx/ Regards, Hans
