On Wed, 14 Dec 2022, Arun R Murthy <arun.r.murthy@xxxxxxxxx> wrote: > The busy timeout logic checks for the AUX BUSY, then waits for the > timeout period and then after timeout reads the register for BUSY or > Success. > Instead replace interrupt with polling so as to read the AUX CTL > register often before the timeout period. Looks like there might be some > issue with interrupt-on-read. Hence changing the logic to polling read. > > v2: replace interrupt with polling read > v3: use usleep_rang instead of msleep, updated commit msg > v4: use intel_wait_for_regiter internal function > > Signed-off-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx> > --- > drivers/gpu/drm/i915/display/intel_dp_aux.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c > index 91c93c93e5fc..fe5ed432a66a 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c > @@ -41,20 +41,20 @@ intel_dp_aux_wait_done(struct intel_dp *intel_dp) > i915_reg_t ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp); > const unsigned int timeout_ms = 10; > u32 status; > - bool done; > > -#define C (((status = intel_de_read_notrace(i915, ch_ctl)) & DP_AUX_CH_CTL_SEND_BUSY) == 0) > - done = wait_event_timeout(i915->display.gmbus.wait_queue, C, > - msecs_to_jiffies_timeout(timeout_ms)); > + __intel_wait_for_register(&i915->uncore, ch_ctl, > + DP_AUX_CH_CTL_SEND_BUSY, > + DP_AUX_CH_CTL_SEND_BUSY, > + 500, timeout_ms, &status); This waits for DP_AUX_CH_CTL_SEND_BUSY to be set, not cleared. Please use intel_de_wait_for_register(). > > - /* just trace the final value */ > - trace_i915_reg_rw(false, ch_ctl, status, sizeof(status), true); > - > - if (!done) > + status = intel_uncore_read_notrace(&i915->uncore, ch_ctl); > + if ((status & DP_AUX_CH_CTL_SEND_BUSY) != 0) Please check intel_de_wait_for_register()'s return value here instead of reading the register once more. You might read the register the register again just to log the value, if intel_de_wait_for_register() returned != 0. But no need to trace log that again. > drm_err(&i915->drm, > "%s: did not complete or timeout within %ums (status 0x%08x)\n", > intel_dp->aux.name, timeout_ms, status); > -#undef C > + > + /* just trace the final value */ > + trace_i915_reg_rw(false, ch_ctl, status, sizeof(status), true); intel_de_wait_for_register() already does the tracing of the final value. > > return status; > } -- Jani Nikula, Intel Open Source Graphics Center
