[PATCH v3 0/2] drm/i915/display: Power request asserting/deasserting

Mika Kahola mika.kahola at intel.com
Thu Oct 31 11:40:25 UTC 2024


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 <mika.kahola at intel.com>

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       | 45 +++++++++++++++++--
 2 files changed, 49 insertions(+), 4 deletions(-)

-- 
2.43.0



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