Quoting Abhinav Kumar (2024-04-03 12:58:50) > > > On 4/3/2024 12:51 PM, Stephen Boyd wrote: > > Quoting Kuogee Hsieh (2024-03-29 12:50:35) > >> Currently qmp_combo_dp_power_on() always return 0 in regardless of > >> return value of cfg->configure_dp_phy(). This patch propagate > >> return value of cfg->configure_dp_phy() all the way back to caller. > > > > Is this found via code inspection or because the phy is failing to power > > on sometimes? I ask because I'm looking at a DP bug on Trogdor with > > chromeos' v6.6 based kernel and wondering if this is related. > > > > No, we actually hit an issue. This issue was originally reported as a > link training issue while bringing up DP on x1e80100. > > While debugging that we noticed that we should not have even proceeded > to link training because the PLL was not getting locked and it was > failing silently since there are no other error prints (and hence the > second part of the patch to improve the error logs), and we do not > return any error code from this driver, we could not catch the PLL > unlocked issue. Did link training succeed in that case and the screen was black? Also, did you figure out why the PLL failed to lock? I sometimes see reports now with an "Unexpected interrupt:" message from the DP driver and the interrupt is the PLL unlocked one (DP_INTR_PLL_UNLOCKED). > > > Also, is the call to phy_power_on() going to be checked in > > the DP driver? > > > > $ git grep -n phy_power_on -- drivers/gpu/drm/msm/dp/ > > drivers/gpu/drm/msm/dp/dp_ctrl.c:1453: phy_power_on(phy); > > Yes, this is a good point. We should also post the patch to add the > error checking in DP driver to fail if phy_power_on fails. Sounds great, thanks.
