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freebsd / drm-kmod

drm driver for FreeBSD
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adjust default value for i915 GPU reset #275

Closed lherschi closed 3 months ago

lherschi commented 9 months ago

The default value was adjusted with commit d78380d, but forgotten to document it in i915_params.c. Since commit 06892ac, however, the value 3 practically no longer exists. This means that the default value can be set to 2 again, as before.

evadot commented 4 months ago

Currently in 6.1 it's still 3, see https://github.com/torvalds/linux/blob/v6.1/drivers/gpu/drm/i915/i915_params.h#L70, it's also 3 in 6.6, see https://github.com/torvalds/linux/blob/v6.6/drivers/gpu/drm/i915/i915_params.h#L73 What are the motivation behind this ?

lherschi commented 4 months ago

The value 3 is not documented anywhere in the FreeBSD code and I could not find any place since commit 06892ac where the 3 is queried. I have not checked whether the value is still used in the Linux driver, but it is also not documented in the two linked repositories.

sysctl -d hw.i915kms.reset hw.i915kms.reset: Attempt GPU resets (0=disabled, 1=full gpu reset, 2=engine reset [default])

evadot commented 3 months ago

It seems that it's been 3 for a long time, and looking at the code it doesn't matter as the default action will still be an engine reset. So we won't modify this code here to keep diff with upstream minimal.