Messages in this thread | | | Date | Thu, 25 Jun 2015 20:30:46 +0300 | Subject | Re: Help configuring kernel for Baytrail system | From | Andy Shevchenko <> |
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On Mon, Jun 15, 2015 at 3:41 PM, Nicolas George <george@nsup.org> wrote: > Hi. > > I am trying to configure a kernel for a Baytrail SoC-based hybrid laptop (a > Lenovo Miix 3-1030). Amongst other things, the battery gauge is not > detected. I suspect it may be related to the following commit: > > # commit 894acb2f823b13afacfe40b02efbd9146af58586 > # Author: David Box <david.e.box@linux.intel.com> > # Date: Thu Jan 15 01:12:17 2015 -0800 > # > # i2c: designware: Add Intel Baytrail PMIC I2C bus support
Why not to ask David (Cc'ed) directly?
> > It is very likely that I am missing a simple compile-time or run-time > option, and in that case, on top of getting the configuration right, I have > a second question: how could I find the solution by myself? > > Here is the problem data: > > - The battery gauge works with the kernel from the Ubuntu 15.4 live image. > Quite a few other things fail to work with that kernel, so using it is not > a solution, but it is proof that it can work. > > - I have tried with 3.16 from Debian, 4.0.1 and 4.1-rc* with custom > configuration, and the battery is completely invisible. Nothing in dmesg. > > - The sysfs entry for the battery is this: > /sys/devices/LNXSYSTM:00/LNXSYBUS:00/80860F41:00/PNP0C0A:00 > It should contain a driver link to bus/acpi/drivers/battery, but it does > not. > > - Adding custom debug messages, I was able to find that > acpi_bus_get_status_handle() evaluates the _STA attribute of the BATC > device to 0, meaning the device is not present. > > - The corresponding code in the ACPI tables is this: > > Device (BATC) > { > [...] > Method (_STA, 0, NotSerialized) // _STA: Status > { > If ((AVBL == One)) > { > BUF7 = CMD7 /* \_SB_.I2C1.CMD7 */ > If ((STAT != Zero)) > { > Return (Zero) > } > > Return (0x1F) > } > > Return (Zero) > } > > but I do not know how to debug further. Enabling full ACPI debug messages > gives so much output that it is unusable. > > - I also suspect that the issue comes from the "dev->pm_runtime_disabled" > flag on the corresponding I2C bus entry: it is enabled by > i2c_dw_eval_lock_support() with a message "I2C bus managed by PUNIT", and > inhibits probing the device. I did not manage to find how to re-enable it. > > > Please let me know if you have any advice on this issue in particular or any > more general documentation on how to investigate I2C and PLATFORM/ACPI-based > systems. > > In the meantime, I have summarized what I was able to get working on this > laptop on the following webpage: > http://nsup.org/~george/comp/linux_lenovo_miix3/ > > Regards, > > -- > Nicolas George
-- With Best Regards, Andy Shevchenko
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