On Thu, May 07, 2020 at 02:39:21PM +0200, Hans de Goede wrote: > On 5/7/20 2:30 PM, Mika Westerberg wrote: > > On Thu, May 07, 2020 at 12:15:09PM +0200, Hans de Goede wrote: > > > On 5/6/20 8:40 AM, Mika Westerberg wrote: +Rafael and ACPICA folks. ... > > I actually think this is the correct solution. Reading ACPI spec it say > > this: > > > > Once _REG has been executed for a particular operation region, > > indicating that the operation region handler is ready, a control > > method can access fields in the operation region > > > > You can interpret it so that _REG gets called when operation region > > handler is ready. It does not say that there needs to be an actual > > operation region even though the examples following all have operation > > region. > > > > I wonder what our ACPICA gurus think about this? Rafael, Bob, Erik? > > > > > We could move the manual _REG call I'm adding to pinctrl-cherry-view.c > > > but that has the same issue of calling _REG twice in many cases. > > > > > > Most (all?) _REG implementations are fine with that, as they just set a > > > variable to 1 (to the Arg1 value). Still calling _REG twice is something > > > which we might want to avoid. > > > > > > As a compromise I've chosen to add the extra unconditional _REG call > > > to pinctrl-cherryview.c because: > > > > > > 1. The problem in the DSDT in question stems from there being 2 > > > different OpRegions for accessing GPIOs which AFAIK is unique to > > > cherryview > > > > > > 2. I've seen many many cherryview DSDT-s and as such I'm confident > > > that calling _REG twice is not an issue on cherryview. > > > > > > > Are the ACPI tables from this system available somewhere? > > > > > > Here you go: > > > https://fedorapeople.org/~jwrdegoede/medion-e1239t-dsdt.dsl > > > > Thanks for sharing! > > > > > The problem is that on line 12624 there is a GPO2.AVBL == One > > > check, before GPO2.DCDT is used. If you then look at line > > > 17688 you see that _REG for the GPO2 device checkes for a > > > space-id of 8 (ACPI_ADR_SPACE_GPIO) to set AVBL > > > > > > But the only OpRegion defined for the GPO2 device, and the > > > OpRegion to which GPO2.DCDT is mapped is the cherryview > > > UserDefined 0x93 GPIO access OpRegion, see line 17760. > > > Since there is no OpRegion for the ACPI_ADR_SPACE_GPIO > > > space-id, ACPICA never calls _REG with Arg0 == 8. > > > > Indeed, I see the issue now. I guess calling _REG always when there is > > handler installed would solve this as well? > > Yes that should solve the issue, that is actualy more or less > what my patch does, but my patch only does it for the > pinctrl-cherryview.c case. And ACPICA guys, in case of thinking about generic solution there, can also have a look into ACPI hotplug code. Something tells me that there may be the very same root cause. -- With Best Regards, Andy Shevchenko
