On Wed, Feb 3, 2021 at 9:16 AM Mika Westerberg
<mika.westerberg@xxxxxxxxxxxxxxx> wrote:
>
> Hi Rafael,
>
> I wonder if you are OK with this patch?
It looks good to me now, please feel free to add my ACK to it.
Thanks!
>
> On Fri, Jan 29, 2021 at 11:32:39AM +0300, Mika Westerberg wrote:
> > From: Mario Limonciello <mario.limonciello@xxxxxxxx>
> >
> > The platform _OSC can change the hardware state when query bit is not
> > set. According to ACPI spec it is recommended that the OS runs _OSC with
> > query bit set until the platform does not mask any of the capabilities.
> > Then it should run it with query bit clear in order to actually commit
> > the changes. Linux has not been doing this for the reasons that there
> > has not been anything to commit, until now.
> >
> > The ACPI 6.4 introduced _OSC for USB4 to allow the OS to negotiate
> > native control over USB4 tunneling. The platform might implement this so
> > that it only activates the software connection manager path when the OS
> > calls the _OSC with the query bit clear. Otherwise it may default to the
> > firmware connection manager, for instance.
> >
> > For this reason modify the _OSC support so that we first execute it with
> > query bit set, then use the returned value as base of the features we
> > want to control and run the _OSC again with query bit clear. This also
> > follows what Windows is doing.
> >
> > Also rename the function to better match what it does.
> >
> > Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > ---
> > drivers/acpi/bus.c | 43 +++++++++++++++++++++++++++++++------------
> > 1 file changed, 31 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> > index 1682f8b454a2..a52cb28c40d8 100644
> > --- a/drivers/acpi/bus.c
> > +++ b/drivers/acpi/bus.c
> > @@ -282,9 +282,9 @@ bool osc_pc_lpi_support_confirmed;
> > EXPORT_SYMBOL_GPL(osc_pc_lpi_support_confirmed);
> >
> > static u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
> > -static void acpi_bus_osc_support(void)
> > +static void acpi_bus_osc_negotiate_platform_control(void)
> > {
> > - u32 capbuf[2];
> > + u32 capbuf[2], *capbuf_ret;
> > struct acpi_osc_context context = {
> > .uuid_str = sb_uuid_str,
> > .rev = 1,
> > @@ -321,17 +321,36 @@ static void acpi_bus_osc_support(void)
> > capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_APEI_SUPPORT;
> > if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
> > return;
> > - if (ACPI_SUCCESS(acpi_run_osc(handle, &context))) {
> > - u32 *capbuf_ret = context.ret.pointer;
> > - if (context.ret.length > OSC_SUPPORT_DWORD) {
> > - osc_sb_apei_support_acked =
> > - capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
> > - osc_pc_lpi_support_confirmed =
> > - capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT;
> > - }
> > +
> > + if (ACPI_FAILURE(acpi_run_osc(handle, &context)))
> > + return;
> > +
> > + capbuf_ret = context.ret.pointer;
> > + if (context.ret.length <= OSC_SUPPORT_DWORD) {
> > kfree(context.ret.pointer);
> > + return;
> > }
> > - /* do we need to check other returned cap? Sounds no */
> > +
> > + /*
> > + * Now run _OSC again with query flag clear and with the caps
> > + * supported by both the OS and the platform.
> > + */
> > + capbuf[OSC_QUERY_DWORD] = 0;
> > + capbuf[OSC_SUPPORT_DWORD] = capbuf_ret[OSC_SUPPORT_DWORD];
> > + kfree(context.ret.pointer);
> > +
> > + if (ACPI_FAILURE(acpi_run_osc(handle, &context)))
> > + return;
> > +
> > + capbuf_ret = context.ret.pointer;
> > + if (context.ret.length > OSC_SUPPORT_DWORD) {
> > + osc_sb_apei_support_acked =
> > + capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
> > + osc_pc_lpi_support_confirmed =
> > + capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT;
> > + }
> > +
> > + kfree(context.ret.pointer);
> > }
> >
> > /* --------------------------------------------------------------------------
> > @@ -1168,7 +1187,7 @@ static int __init acpi_bus_init(void)
> > * _OSC method may exist in module level code,
> > * so it must be run after ACPI_FULL_INITIALIZATION
> > */
> > - acpi_bus_osc_support();
> > + acpi_bus_osc_negotiate_platform_control();
> >
> > /*
> > * _PDC control method may load dynamic SSDT tables,
> > --
> > 2.29.2
