[Intel-gfx] [PATCH 0/2] drm: link status property and DP link training failure handling

[Pandiyan, Dhinakaran]

On Fri, 2016-12-16 at 16:47 +0200, Jani Nikula wrote:
> On Fri, 16 Dec 2016, Daniel Vetter <daniel at ffwll.ch> wrote:
> > On Fri, Dec 16, 2016 at 12:29:05PM +0200, Jani Nikula wrote:
> >> The two remaining patches from [1], rebased.
> >> 
> >> BR,
> >> Jani.
> >> 
> >> 
> >> [1] http://mid.mail-archive.com/1480984058-552-1-git-send-email-manasi.d.navare@intel.com
> >
> > Just for the record, I think the only thing missing here is the Xorg
> > review on the -modesetting patch. As soon as we have that I can vacuum
> > this up (probably best through drm-misc, but not sure).
> 
> Yeah I rebased this (and provided a debug hack privately) so Martin can
> test the modesetting changes.
> 
> BR,
> Jani.
> 
> 

I tested the -modesetting patch, which Martin had provided to Manasi,
with a compliance testing device (DPR-120) that can simulate link
training failure. The link rate correctly lowered after the link_status
property was set to BAD by the kernel and the userspace responded with a
modeset. 

One thing that was not straight forward to figure out was I had to boot
with i915.nuclear_pageflip=1. Is it documented somewhere that the
property needs DRIVER_ATOMIC to be set, or is it implicit?

The other thing I had trouble with -modesetting was, there was no
modeset following a long pulse from the sink at the begging of the test.
I had to force a modeset by changing the resolution so that the link
training path is executed. However, the link training failure induced a
modeset without any intervention.

-DK


> > -Daniel
> >
> >> 
> >> 
> >> Manasi Navare (2):
> >>   drm: Add a new connector atomic property for link status
> >>   drm/i915: Implement Link Rate fallback on Link training failure
> >> 
> >>  drivers/gpu/drm/drm_atomic.c                  | 16 +++++++++
> >>  drivers/gpu/drm/drm_atomic_helper.c           | 15 ++++++++
> >>  drivers/gpu/drm/drm_connector.c               | 52 +++++++++++++++++++++++++++
> >>  drivers/gpu/drm/i915/intel_dp.c               | 27 ++++++++++++++
> >>  drivers/gpu/drm/i915/intel_dp_link_training.c | 22 ++++++++++--
> >>  drivers/gpu/drm/i915/intel_drv.h              |  3 ++
> >>  include/drm/drm_connector.h                   | 19 ++++++++++
> >>  include/drm/drm_mode_config.h                 |  5 +++
> >>  include/uapi/drm/drm_mode.h                   |  4 +++
> >>  9 files changed, 161 insertions(+), 2 deletions(-)
> >> 
> >> -- 
> >> 2.1.4
> >> 
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>