drm/i915: Move skl/bxt gt specific workarounds to ring init

Some registers are, naturally, lost in gpu reset/suspend cycle.
And some registers, for example in display domain, are not subject
to gpu reset so they retain their contents.

As hang recovery triggers a reset, recoverable gpu hang can currently
flush out essential workarounds and cause havoc later on.

When register GEN8_GARBNTL is missing the WaEnableGapsTsvCreditFix:skl,
it can cause random system hangs [1]. This workaround was added in:
commit 245d96670d26 ("drm/i915:skl: Add WaEnableGapsTsvCreditFix")
But another set of system hangs were observed and the failure pattern
indicated that there was random gpu hang preceding the system hang [2].
This lead to the realization that we lose this workaround and BDW_SCRATCH1
on reset.

Add these workarounds setup in display init to skl/bxt ring init
where LRI workarounds are also setup. This way their setup is not
dependent on display side init.

References: [1] https://bugs.freedesktop.org/show_bug.cgi?id=90854
References: [2] https://bugs.freedesktop.org/show_bug.cgi?id=92315
Reported-by: Tomi Sarvela <[email protected]>
Cc: Tomi Sarvela <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Signed-off-by: Mika Kuoppala <[email protected]>
Reviewed-by: Chris Wilson <[email protected]>
Tested-by: Tomi Sarvela <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>

0 files changed, 0 insertions, 0 deletions