From: Bjorn Andersson quic_bjorande@quicinc.com
Commit 'e3e56c050ab6 ("soc: qcom: rpmhpd: Make power_on actually enable the domain")' aimed to make sure that a power-domain that is being enabled without any particular performance-state requested will at least turn the rail on, to avoid filling DeviceTree with otherwise unnecessary required-opps properties.
But in the event that aggregation happens on a disabled power-domain, with an enabled peer without performance-state, both the local and peer corner are 0. The peer's enabled_corner is not considered, with the result that the underlying (shared) resource is disabled.
One case where this can be observed is when the display stack keeps mmcx enabled (but without a particular performance-state vote) in order to access registers and sync_state happens in the rpmhpd driver. As mmcx_ao is flushed the state of the peer (mmcx) is not considered and mmcx_ao ends up turning off "mmcx.lvl" underneath mmcx. This has been observed several times, but has been painted over in DeviceTree by adding an explicit vote for the lowest non-disabled performance-state.
Fixes: e3e56c050ab6 ("soc: qcom: rpmhpd: Make power_on actually enable the domain") Reported-by: Johan Hovold johan@kernel.org Closes: https://lore.kernel.org/linux-arm-msm/ZdMwZa98L23mu3u6@hovoldconsulting.com/ Cc: stable@vger.kernel.org Signed-off-by: Bjorn Andersson quic_bjorande@quicinc.com --- This issue is the root cause of a display regression on SC8280XP boards, resulting in the system often resetting during boot. It was exposed by the refactoring of the DisplayPort driver in v6.8-rc1. --- drivers/pmdomain/qcom/rpmhpd.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/pmdomain/qcom/rpmhpd.c b/drivers/pmdomain/qcom/rpmhpd.c index 3078896b1300..47df910645f6 100644 --- a/drivers/pmdomain/qcom/rpmhpd.c +++ b/drivers/pmdomain/qcom/rpmhpd.c @@ -692,6 +692,7 @@ static int rpmhpd_aggregate_corner(struct rpmhpd *pd, unsigned int corner) unsigned int active_corner, sleep_corner; unsigned int this_active_corner = 0, this_sleep_corner = 0; unsigned int peer_active_corner = 0, peer_sleep_corner = 0; + unsigned int peer_enabled_corner;
if (pd->state_synced) { to_active_sleep(pd, corner, &this_active_corner, &this_sleep_corner); @@ -701,9 +702,11 @@ static int rpmhpd_aggregate_corner(struct rpmhpd *pd, unsigned int corner) this_sleep_corner = pd->level_count - 1; }
- if (peer && peer->enabled) - to_active_sleep(peer, peer->corner, &peer_active_corner, + if (peer && peer->enabled) { + peer_enabled_corner = max(peer->corner, peer->enable_corner); + to_active_sleep(peer, peer_enabled_corner, &peer_active_corner, &peer_sleep_corner); + }
active_corner = max(this_active_corner, peer_active_corner);
--- base-commit: b401b621758e46812da61fa58a67c3fd8d91de0d change-id: 20240226-rpmhpd-enable-corner-fix-c5e07fe7b986
Best regards,