On Sun, Sep 23, 2018 at 03:58:05PM +0200, Hans de Goede wrote:
> Hi All,
>
> Here is v2 of my patch-series to make sure that on BYT/CHT systems the I2C
> controller connected to the PMIC gets resumed before the GPU.
>
> New in v2:
> -Dropped "ACPI / LPSS: Only add device links from consumer to supplier" patch
> this was based on wrongly reading the code and the code it removed is fine
> -Added "ACPI / LPSS: Add a device link from the GPU to the BYT I2C5 controller"
> it turns out we need to order things correctly on BYT too, otherwise things
> also fail, but in a much nastier way then on CHT, see the commit msg of
> the new patch
>
> Below is the original coverletter of v1 of the patch-set:
>
> On some Cherry Trail systems the GPU ACPI fwnode has power-resources which
> point to the PMIC, which is connected over the LPSS I2C7 controller.
>
> Currently the I2C controller resumes after the GPU is resumed leading 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 series fixes this. This actually requires 3 separate fixes each of
> which is necessary and the error only goes away once all 3 are in place:
>
> 1) Patches 1-3 rework the acpi_lpss.c device-link code added by commit
> e6ce0ce34f65 ("ACPI / LPSS: Add device link for CHT SD card dependency on I2")
> so that the code can be used to add a device link between an ACPI LPSS
> device and a PCI device (the GPU).
> Patch 4 an 5 then actually add the device-links. Note that the other 2 fixes
> may give the impression that this fix is not necessary, that is not the
> case we most both make sure that the resume happens during the right
> resume phase *and* that within that phase it is done before the GPU resume
>
> 2) The GPU is a PCI device and PCI devices are brought up (moved from D3 to D0)
> in the noirq phase already. Normally ACPI LPSS device gets resumed in the
> resume_early phase. The ordering from 1) only orders things within the same
> phase. To make sure the I2C controller is ready before the GPU resumes
> we must resume LPSS I2C controllers (on BYT and CHT) from the noirq phase.
> This is done in patch 6.
>
> 3) Now we get a timeout waiting for the IRQ in the i2c-designware driver
> since IRQs are disabled in the noirq resume phase. Patch 7 marks the IRQ
> for BYT/CHT ACPI-LPSS i2c-designware controllers with IRQF_NO_SUSPEND.
>
> These patches are posted a single series since together they fix a single
> problem. But both the acpi_lpss and i2c-designware code have seen some
> churn in -next and not having patch 7 in place results in the error staying
> the same, so patches 1-6 can be merged indepedently without causing any
> regresssions (and patch 7 without 1-6 is not an issue either).
>
> Therefor I suggest that the acpi_lpss.c and the i2c-designware changes get
> merged through separate trees.
>
Thanks for this work!
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Regards,
>
> Hans
>
--
With Best Regards,
Andy Shevchenko
