Re: [PATCH v2 2/7] ACPI / LPSS: allow to use specific PM domain during ->probe()

Jarkko Nikula
2015-11-26T16:30:37Z

On 11/26/2015 05:19 PM, Andy Shevchenko wrote:
> This is an amendment to previously pushed commit 01ac170ba29a (ACPI / LPSS:
> allow to use specific PM domain during ->probe()). We can't assign anything to
> the platform device on ADD_DEVICE stage since it might be changed during
> unbound / bind cycle.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> drivers/acpi/acpi_lpss.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
> index f9e0d09..e840229 100644
> --- a/drivers/acpi/acpi_lpss.c
> +++ b/drivers/acpi/acpi_lpss.c
> @@ -705,8 +705,14 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
> }
>
> switch (action) {
> - case BUS_NOTIFY_ADD_DEVICE:
> + case BUS_NOTIFY_BIND_DRIVER:
> pdev->dev.pm_domain = &acpi_lpss_pm_domain;
> + break;
> + case BUS_NOTIFY_BIND_DRIVER_ERROR:
> + case BUS_NOTIFY_UNBOUND_DRIVER:
> + pdev->dev.pm_domain = NULL;
> + break;
> + case BUS_NOTIFY_ADD_DEVICE:

This won't fix like revert of original commit does. Primary problem here
is that there is no explicit power on at all during LPSS device probe
because dev->pm_domain is set before probing.

driver_probe_device
platform_drv_prove
dev_pm_domain_attach
acpi_dev_pm_attach
returns instantly because of dev->pm_domain is set

Problem got unnoticed because devices are on during boot but
rmmod/modprobe cycle will hit it.

With this patch situation remains the same but works if you assign the
domain after probing when BUS_NOTIFY_BOUND_DRIVER notification comes
(s/BUS_NOTIFY_BIND_DRIVER/BUS_NOTIFY_BOUND_DRIVER/ above).

--
Jarkko