On Wed, 27 Apr 2011 18:27:51 +1000, Paul McGarry <p...@paulmcgarry.com> wrote: > On Wed, Apr 27, 2011 at 4:49 PM, Chris Wilson <ch...@chris-wilson.co.uk> > wrote: > > DP has worked for most people the last 18 months or so... There is always > > to unhappy exception. Can you please append drm.debug=0xe to you kernel > > boot parameters and attach the dmesg from booting? > > -Chris > > Hi Chris, > > Please find that attached. > It is from a boot with only the DP monitor attached.
The unusual sequence appears to be: [ 30.081906] [drm:intel_dp_i2c_init], i2c_init DPDDC-B [ 30.082413] [drm:intel_dp_aux_ch], dp_aux_ch timeout status 0x5143003e [ 30.082415] [drm:intel_dp_i2c_aux_ch], aux_ch failed -110 [ 30.082921] [drm:intel_dp_aux_ch], dp_aux_ch timeout status 0x5143003e [ 30.082923] [drm:intel_dp_i2c_aux_ch], aux_ch failed -110 [ 30.082986] [drm:intel_dp_i2c_init], i2c_init DPDDC-C [ 30.083193] [drm:intel_dp_i2c_aux_ch], aux_i2c nack [ 30.083401] [drm:intel_dp_i2c_aux_ch], aux_i2c nack [ 30.083427] [drm:intel_dp_i2c_init], i2c_init DPDDC-D [ 30.083934] [drm:intel_dp_aux_ch], dp_aux_ch timeout status 0x5143003e [ 30.083935] [drm:intel_dp_i2c_aux_ch], aux_ch failed -110 [ 30.084442] [drm:intel_dp_aux_ch], dp_aux_ch timeout status 0x5143003e [ 30.084443] [drm:intel_dp_i2c_aux_ch], aux_ch failed -110 I wonder what side-effects that explicit NAK from the monitor does during initialisation of the DP i2c channel. During detection we also see a discrepancy for DPDDC-D: [ 30.172250] [drm:drm_helper_probe_single_connector_modes], [CONNECTOR:19:DP-2] [ 30.172757] [drm:intel_dp_aux_ch], dp_aux_ch timeout status 0x5013003e [ 30.172758] [drm:ironlake_dp_detect], DPCD: 0000 So instead of sending the expected 20 bytes to query the connection, we just sent the 1 byte header. It seems our problems start with that nack. Lets start with a WARN for the AUX_I2C_REPLY_NACK so that I can see the callpath for that initial probe and so work out the command being sent that the monitor doesn't like. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx
