On Sat, Sep 08, 2018 at 08:08:13PM +0200, Hans de Goede wrote:
> lpss_iosf_enter_d3_state() checks if all hw-blocks using the DMA
> controllers are in d3 before powering down the DMA controllers.
>
> But on devices, where the I2C bus connected to the PMIC is shared by
> the PUNIT, the controller for that bus will never reach d3 since it has
> an effectively empty _PS3 method. Instead it appears to automatically
> power-down during S0i3 and we never see it as being in d3.
>
> This causes the DMA controllers to never be powered-down on these devices,
> causing them to never reach S0i3. This commit uses the ACPI _SEM method
> to detect if an I2C bus is shared with the PUNIT and if it is, it removes
> it from the mask of devices which lpss_iosf_enter_d3_state() checks for.
>
> This fixes these devices never reaching any S0ix states.
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> drivers/acpi/acpi_lpss.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
> index 969bf8d515c0..83875305b1d4 100644
> --- a/drivers/acpi/acpi_lpss.c
> +++ b/drivers/acpi/acpi_lpss.c
> @@ -99,6 +99,9 @@ struct lpss_private_data {
> u32 prv_reg_ctx[LPSS_PRV_REG_COUNT];
> };
>
> +/* Devices which need to be in D3 before lpss_iosf_enter_d3_state() proceeds */
> +static u32 pmc_atom_d3_mask = 0xfe000ffe;
> +
> /* LPSS run time quirks */
> static unsigned int lpss_quirks;
>
> @@ -175,6 +178,21 @@ static void byt_pwm_setup(struct lpss_private_data *pdata)
>
> static void byt_i2c_setup(struct lpss_private_data *pdata)
> {
> + const char *uid_str = acpi_device_uid(pdata->adev);
> + acpi_handle handle = pdata->adev->handle;
> + unsigned long long shared_host = 0;
> + acpi_status status;
> + long uid = 0;
Hmm, I wonder if uid=0 is actually valid? IIRC they start from 0 and go
forward from that.
> +
> + /* Expected to always be true, but better safe then sorry */
> + if (uid_str)
> + uid = simple_strtol(uid_str, NULL, 10);
> +
> + /* Detect I2C bus shared with PUNIT and ignore its d3 status */
> + status = acpi_evaluate_integer(handle, "_SEM", NULL, &shared_host);
> + if (ACPI_SUCCESS(status) && shared_host && uid)
> + pmc_atom_d3_mask &= ~(BIT_LPSS2_F1_I2C1 << (uid - 1));
