On Fri, Feb 10, 2017 at 02:44:20PM -0800, Palmer Dabbelt wrote: > DisplayPort no longer hotplugs on my machine (a 2014 MacBook Pro > attached to an ASUS PB287Q). I believe the problem is that long pulses > are no longer triggering intel_dp_check_link_status. That shouldn't itsefl cause problems with hotplugs. It could cause problems if you hotplug displays without a proper randr client running in which case the link is left running when you unplug the displays and then gets retrained when you plug a display back in. That doesn't explain why intel_dp_check_link_status() wouldn't get called though. It should be called via intel_dp_detect() -> intel_dp_long_pulse(). > I bisected the > problem down to (7d23e3c37 "drm/i915: Cleaning up intel_dp_hpd_pulse") > and it appears the only material change there was to remove one of those > calls. > > This commit adds the check_link_status call back in, which causes hotplug to > work again for me. I test this via a "xset dpms force off". Note that this is > very similar to <https://bugs.freedesktop.org/show_bug.cgi?id=89453>, but it's > back again. > > I've tested this against 4.9, and it applies against the current head. > > See <https://bugs.freedesktop.org/show_bug.cgi?id=99766>. > > Here's the commit that triggered the regression: > > commit 7d23e3c37bb3fc6952dc84007ee60cb533fd2d5c > Author: Shubhangi Shrivastava <shubhangi.shrivastava@xxxxxxxxx> > Date: Wed Mar 30 18:05:23 2016 +0530 > > drm/i915: Cleaning up intel_dp_hpd_pulse > > Current DP detection has DPCD operations split across > intel_dp_hpd_pulse and intel_dp_detect which contains > duplicates as well. Also intel_dp_detect is called > during modes enumeration as well which will result > in multiple dpcd operations. So this patch tries > to solve both these by bringing all DPCD operations > in one single function and make intel_dp_detect > use existing values instead of repeating same steps. > > Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_dp.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > index 0b8e8eb..32ca4be 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -4831,6 +4831,10 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd) > long_hpd ? "long" : "short"); > > if (long_hpd) { > + drm_modeset_lock(&dev->mode_config.connection_mutex, NULL); > + intel_dp_check_link_status(intel_dp); > + drm_modeset_unlock(&dev->mode_config.connection_mutex); > + > intel_dp->detect_done = false; > return IRQ_NONE; > } > -- > 2.10.2 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
