On Sun, 21 Mar 2010, Jukka Ruohonen wrote:
This part certainly gets complicated, and a C3 variation may sound like the right thing to do. I think it would be best if the drivers could reset the limits internally with an appropriate reset command issued directly to the underlying hardware as opposed to the bookkeeping of the values in the software (otherwise, what would happen after a soft reboot?), but I'm unaware regarding whether or not such hardware support is usually present.Additionally, the limit values can be in read-only registers, etc.
If the registers are read-only, the driver should not provide a xxx_set_limits() callback. Furthermore, it should either prevent the user from changing the limits values (with the FMONNOTSUPP flag) or leave value/limit checking to the software framework. In either case, if the registers are read-only, the driver falls into category A or B.
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