On Monday, May 20, 2013 01:25:30 PM Mika Westerberg wrote: > On Mon, May 13, 2013 at 02:44:32PM +0300, Mika Westerberg wrote: > > On Mon, May 13, 2013 at 01:38:46PM +0200, Rafael J. Wysocki wrote: > > > On Monday, May 13, 2013 01:27:51 PM Mika Westerberg wrote: > > > > ACPI Timer() opcode should return monotonically increasing clock with 100ns > > > > granularity. Implement this with the help of ktime_get(). > > > > > > > > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > > > > > > That looks reasobable. Have you tested it? > > > > Very lightly. Basically I added some debug printks() between two > > successsive calls of Timer() and it seemed like it returned correct time. > > > > It is certainly better than returning t+1 every time Timer() is called :) > > I did somewhat better test for this. I added following ASL code: > > ... > Store(Timer, Local1) > Sleep(10) > Divide(Subtract(Timer, Local1), 10000,, Local1) > Sleep(Local1) > > Store(Timer, Local1) > Sleep(200) > Divide(Subtract(Timer, Local1), 10000,, Local1) > Sleep(Local1) > > Store(Timer, Local1) > Sleep(1300) > Divide(Subtract(Timer, Local1), 10000,, Local1) > Sleep(Local1) > > The second sleep should be pretty close to the first one. > > Without this patch I get: > > [ 11.488100] ACPI: acpi_os_get_timer() TBD > [ 11.492150] ACPI: Sleep(10) > [ 11.502993] ACPI: Sleep(0) > [ 11.506315] ACPI: Sleep(200) > [ 11.706237] ACPI: Sleep(0) > [ 11.709550] ACPI: Sleep(1300) > [ 13.008929] ACPI: Sleep(0) > > With the patch applied I get: > > [ 11.486786] ACPI: Sleep(10) > [ 11.499029] ACPI: Sleep(12) > [ 11.512350] ACPI: Sleep(200) > [ 11.712282] ACPI: Sleep(200) > [ 11.912170] ACPI: Sleep(1300) > [ 13.211577] ACPI: Sleep(1300) > > The above looks much more correct to me. That demostrates the problem nicely. Can you please add the above info to the patch changelog? Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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
