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.westerb...@linux.intel.com>
> >
> > 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.
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