Commit 20b0dfa86bef0e80b41b0e5ac38b92f23b6f27f9 upstream.

The original commit depended on a rework commit (724fc856c09e ("drm/vc4: hdmi: Split the CEC disable / enable functions in two")) that (rightfully) didn't reach stable.

However, probably because the context changed, when the patch was applied to stable the pm_runtime_put called got moved to the end of the vc4_hdmi_cec_adap_enable function (that would have become vc4_hdmi_cec_disable with the rework) to vc4_hdmi_cec_init.

This means that at probe time, we now drop our reference to the clocks and power domains and thus end up with a CPU hang when the CPU tries to access registers.

The call to pm_runtime_resume_and_get() is also problematic since the .adap_enable CEC hook is called both to enable and to disable the controller. That means that we'll now call pm_runtime_resume_and_get() at disable time as well, messing with the reference counting.

The behaviour we should have though would be to have pm_runtime_resume_and_get() called when the CEC controller is enabled, and pm_runtime_put when it's disabled.

We need to move things around a bit to behave that way, but it aligns stable with upstream.

Cc: stable@vger.kernel.org # 5.10.x Cc: stable@vger.kernel.org # 5.15.x Cc: stable@vger.kernel.org # 5.16.x Reported-by: Michael Stapelberg michael+drm@stapelberg.ch Signed-off-by: Maxime Ripard maxime@cerno.tech --- drivers/gpu/drm/vc4/vc4_hdmi.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 8465914892fa..e6aad838065b 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -1739,18 +1739,18 @@ static int vc4_hdmi_cec_adap_enable(struct cec_adapter *adap, bool enable) u32 val; int ret;

- ret = pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev); - if (ret) - return ret; - - val = HDMI_READ(HDMI_CEC_CNTRL_5); - val &= ~(VC4_HDMI_CEC_TX_SW_RESET | VC4_HDMI_CEC_RX_SW_RESET | - VC4_HDMI_CEC_CNT_TO_4700_US_MASK | - VC4_HDMI_CEC_CNT_TO_4500_US_MASK); - val |= ((4700 / usecs) << VC4_HDMI_CEC_CNT_TO_4700_US_SHIFT) | - ((4500 / usecs) << VC4_HDMI_CEC_CNT_TO_4500_US_SHIFT); - if (enable) { + ret = pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev); + if (ret) + return ret; + + val = HDMI_READ(HDMI_CEC_CNTRL_5); + val &= ~(VC4_HDMI_CEC_TX_SW_RESET | VC4_HDMI_CEC_RX_SW_RESET | + VC4_HDMI_CEC_CNT_TO_4700_US_MASK | + VC4_HDMI_CEC_CNT_TO_4500_US_MASK); + val |= ((4700 / usecs) << VC4_HDMI_CEC_CNT_TO_4700_US_SHIFT) | + ((4500 / usecs) << VC4_HDMI_CEC_CNT_TO_4500_US_SHIFT); + HDMI_WRITE(HDMI_CEC_CNTRL_5, val | VC4_HDMI_CEC_TX_SW_RESET | VC4_HDMI_CEC_RX_SW_RESET); HDMI_WRITE(HDMI_CEC_CNTRL_5, val); @@ -1778,7 +1778,10 @@ static int vc4_hdmi_cec_adap_enable(struct cec_adapter *adap, bool enable) HDMI_WRITE(HDMI_CEC_CPU_MASK_SET, VC4_HDMI_CPU_CEC); HDMI_WRITE(HDMI_CEC_CNTRL_5, val | VC4_HDMI_CEC_TX_SW_RESET | VC4_HDMI_CEC_RX_SW_RESET); + + pm_runtime_put(&vc4_hdmi->pdev->dev); } + return 0; }

@@ -1889,8 +1892,6 @@ static int vc4_hdmi_cec_init(struct vc4_hdmi *vc4_hdmi) if (ret < 0) goto err_remove_handlers;

- pm_runtime_put(&vc4_hdmi->pdev->dev); - return 0;

err_remove_handlers: