[v4,0/2] drm/i915/display: Power request asserting/deasserting

Message

Mika Kahola Nov. 1, 2024, 1:39 p.m. UTC

There is a HW issue that arises when there are race conditions
between TCSS entering/exiting TC7 or TC10 states while the
driver is asserting/deasserting TCSS power request. As a
workaround, Display driver will implement a mailbox sequence
to ensure that the TCSS is in TC0 when TCSS power request is
asserted/deasserted.

The sequence is the following

1. Read mailbox command status and wait until run/busy bit is
   clear
2. Write mailbox data value '1' for power request asserting
   and '0' for power request deasserting
3. Write mailbox command run/busy bit and command value with 0x1
4. Read mailbox command and wait until run/busy bit is clear
   before continuing power request.

while at it, let's start using struct intel_display instead of
struct drm_i915_private as well.

Signed-off-by: Mika Kahola <[e-mail]>

Mika Kahola (2):
  drm/i915/xe3lpd: Power request asserting/deasserting
  drm/i915/display: Use struct intel_display instead of struct
    drm_i915_private

 .../gpu/drm/i915/display/intel_cx0_phy_regs.h |  8 ++++
 drivers/gpu/drm/i915/display/intel_tc.c       | 44 +++++++++++++++++--
 2 files changed, 48 insertions(+), 4 deletions(-)