Hi, On Mon, Apr 17, 2017 at 09:39:35AM +0000, Zheng, Lv wrote: > Hi, > > > From: Guenter Roeck [mailto:linux@xxxxxxxxxxxx] > > Subject: Re: [PATCH] ACPICA: Export mutex functions > > > > On Wed, Apr 12, 2017 at 03:29:55PM +0000, Moore, Robert wrote: > > > The ACPICA mutex functions are based on the host OS functions, so they don't really buy you anything. > > You should just use the native Linux functions. > > > > > > > You mean they don't really acquire the requested ACPI mutex, > > and the underlying DSDT which declares and uses the mutex > > just ignores if the mutex was acquired by acpi_acquire_mutex() ? > > > > To clarify: You are saying that code such as > > > > acpi_status status; > > > > status = acpi_acquire_mutex(NULL, "\\_SB.PCI0.SBRG.SIO1.MUT0", 0x10); > > if (ACPI_FAILURE(status)) { > > pr_err("Failed to acquire ACPI mutex\n"); > > return -EBUSY; > > } > > Why do you need to access \_SB.PCI0.SBRG.SIO1.MUT0? > OSPM should only invoke entry methods predefined by ACPI spec or whatever specs. > There shouldn't be any needs that a driver acquires an arbitrary AML mutex. > You do not seem to have justified the usage model, IMO. > I am sorry, I have no idea how to do that. I can see that the resource in question (IO address 0x2e/0x2f) is accessed from the DSDT, that the resource is mutex protected, and that accesses to the same IO address from the Linux kernel are unreliable unless I acquire the mutex in question. At the same time, I can see that request_muxed_region() succeeds, so presumably ACPI does not reserve the region for its exclusive use. It may well be that the "official" response to this problem is "you must not instantiate a watchdog, environmental monitor, or gpio driver (or anything else provided by the Super-IO chip that requires access to those ports) on this platform in Linux". Is that what you are suggesting ? Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
