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SubjectRe: [lm-sensors] [RFC] (almost) booting allyesconfig -- please don't poke super-io without request_region
Milton Miller wrote:
> After the following patch to mark the isa region busy and applying a few
> patches[1], I was able to kexec boot into an all-yes-config kernel from
> linux-next, with the following KCONFIG_ALLCONFIG file:
>
> # CONFIG_KALLSYMS_EXTRA_PASS is not set
> # CONFIG_CRASH_DUMP is not set
> CONFIG_PPC_EARLY_DEBUG_RTAS_CONSOLE=y
> # CONFIG_NSC_FIR is not set
> # CONFIG_SMC_IRCC_FIR is not set
> # CONFIG_ALI_FIR is not set
> # CONFIG_TCG_NSC is not set
> # CONFIG_TCG_ATMEL is not set
> # CONFIG_SENSORS_F71805F is not set
> # CONFIG_SENSORS_F71882FG is not set
> # CONFIG_SENSORS_F75375S is not set
> # CONFIG_SENSORS_IT87 is not set
> # CONFIG_SENSORS_PC87360 is not set
> # CONFIG_SENSORS_PC87427 is not set
> # CONFIG_SENSORS_DME1737 is not set
> # CONFIG_SENSORS_SMSC47M1 is not set
> # CONFIG_SENSORS_SMSC47B397 is not set
> # CONFIG_SENSORS_VT1211 is not set
> # CONFIG_SENSORS_W83627HF is not set
> # CONFIG_SENSORS_W83627EHF is not set
>
> While the first two might not be required, and the third is just
> selecting the right platform, it would be nice to get the drivers
> to play as well as the rest of the kernel.
>
> The drivers all are for super-io chips, either irda/FIR drivers or hwmon,
> and poke at isa ports without checking request_region.
>

Erm,

The superio sensor drivers only poke the superio chip registers without request
region during the probe phase, iow they try to detect the chip, using a widely
document and standardized (part of isa pnp AFAIK) procedure on standardized ports.

Let me try to explain a bit about superio chips, they have 2 superio control
registers (an index and data register) with which things like a manufacturer
and device id can be read, besides these id registers they also have a set of
registers with config for different logical devices. Once the id is matched,
the driver knows which logical device config to read, reads a (different) isa
base address + range from the logical device config, and then does a
request_region on the region actually used by the logical device.

The superio control registers are thus a sort of pci configuration space if you
want, doing a request_region on these is not such a good idea, as multiple
drivers (for different logical devices within the superio device) may use
these, so trying to gain exclusive access will lead to troubles.

I hope with this info about the problem space, that you maybe have a suggestion
on howto fix this?

Regards,

Hans
>



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