[PATCH 8/8] drm/amd/pm: drop the support for manual fan speed setting on SMU13.0.7

[Matt Coffin]

On 1/9/23 23:48, Quan, Evan wrote:
> [AMD Official Use Only - General]
> 
> We need these to address the fan speed setting failure reported for the new SMU13 asics.
My opinion shouldn't matter much given sparseness of activity, but, 
despite his... short tonality, I agree with Lijo's assessment there.

As someone less familiar with the code base, the use of "multiple 
sources of truth" contributes to making it harder to understand and ramp 
up with.

As for the sysfs fan control issue itself, this won't really "fix" the 
issue, but rather just remove write permissions from the hwmon files (if 
my testing+understanding is right), so it wouldn't seem to be a 
hyper-critical deliverable to me as a random outsider looking in 
(despite being effected by the issue personally). Even with that 
interface removed, there isn't another way to control the "auto" fans, 
as the FW reports it doesn't support that capability in the OD table, 
and ignores anything set therein for that purpose. Hopefully that's 
temporary until FW gets fixed?

I also think the behavior of the other proposed solution (removal of 
interface functions from the ppt_funcs), is objectively a better 
experience w/r/t outcome. If the functions are NULL, then the hwmon 
device files go away *completely*, instead of just being masked from 
write permission, which would make the message clearer to the end user 
that it's not an error, but an actual lack of functionality.

Cheers, sorry I couldn't help, but wanted to at least have something 
come of the last few days I spent implmenting OD on SMU13 for nothing!

~Matt