Messages in this thread | | | Date | Sat, 8 Oct 2022 21:59:14 +0200 | Subject | Re: [GIT PULL] Backlight for v6.1 | From | Hans de Goede <> |
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Hi Linus,
On 10/8/22 21:02, Linus Torvalds wrote: > On Sat, Oct 8, 2022 at 11:31 AM Andy Shevchenko > <andriy.shevchenko@linux.intel.com> wrote: >> >> The Intel PMICs are the beasts when we want to run the code on the real >> hardware. > > Yeah, I don't expect he driver to work on real hardware,
I'm not sure what you mean here. I guess you mean that you do not expect to be able to test the driver on real hw yourself?
I have several x86 tablets with this PMIC and the driver does actually work on real hw, I test it regularly.
As for the admittedly weird:
depends on I2C_DESIGNWARE_PLATFORM=y
dependency, as Andy mentioned on most of these devices the ACPI tables (often the _PS0 / _PS3 power on/off methods) poke at the PMIC through ACPI Opregions which are registered through the MFD driver. This all needs to be available early on which is why I2C_DESIGNWARE_PLATFORM needs to be builtin (the PMIC is connected to the system through a designware I2C controller).
When built as a module we get a whole bunch of ACPI subsys errors about OpRegion calls to a non registered OpRegion in dmesg and this can also results in real bugs like e.g. a touchscreen not working because it was not powered on.
After several bug reports about this I decided to add this dependency to force distros to built I2C_DESIGNWARE_PLATFORM into the main vmlinuz image if they want to enable these drivers.
<snip>
> depends on I2C_DESIGNWARE_PLATFORM=y > > might be better with a "|| COMPILE_TEST" to at least find the build > issues, even if actual runtime testing is a different anumal entirely.
Adding "|| COMPILE_TEST" sounds like a good idea to me. Note that as I tried to explain the: depends on I2C_DESIGNWARE_PLATFORM=y
is actually there to avoid known runtime issues with having that built as a module in combination with this (and a few other similar) PMIC drivers.
Regards,
Hans
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