• Hans de Goede's avatar
    ACPI / LPSS: Resume BYT/CHT I2C controllers from resume_noirq · 48402cee
    Hans de Goede authored
    On some Cherry Trail systems the GPU ACPI fwnode has power-resources which
    point to the PMIC, which is connected over a LPSS I2C controller.
    
    We add a device-link to make sure that the I2C controller is resumed before
    the GPU is. But the pci-core changes the power-state of PCI devices from
    D3 to D0 at noirq time (to restore the PCI config registers) and before
    this commit we were bringing up the I2C controllers from a resume_early
    handler which runs later. More specifically the pm-core will first run
    all resume_noirq handlers in order and then all resume_early handlers.
    
    So we must not only make sure that the handlers are run in the right order,
    but also that the resume of the I2C controller is done at noirq time.
    
    The behavior before this commit, resuming the I2C controller from a
    resume_early handler leads to the following errors:
    
     i2c_designware 808622C1:06: controller timed out
     ACPI Error: AE_ERROR, Returned by Handler for [UserDefinedRegion]
     ACPI Error: Method parse/execution failed \_SB.P18W._ON, AE_ERROR
     video LNXVIDEO:00: Failed to change power state to D0
    
    This commit changes the acpi_lpss.c code to resume the BYT/CHT I2C
    controllers at resume_noirq time fixing this.
    Tested-by: default avatarJarkko Nikula <jarkko.nikula@linux.intel.com>
    Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
    Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    48402cee
acpi_lpss.c 32.5 KB