[RFC] [PATCH 00/14] HPD/connector-polling rework

[Daniel Vetter]

Hi all,

I've got fed up with our sorry state of connector detection and rampant edid re
and rere-reading.

This patch series lays the groundwork in the drm helpers so that drivers can
avoid all this madness (at least on working hw) and properly cache the edid.

With the additional changes for drm/i915, the edid is now read _once_ per plug
event (or at boot-up/resume time). A further step would be to integrate the
hotplug handling into the driver itself and only call ->detect on the connectors
for which the irq handler received a hotplug event.

By adding POLL_FORCE drivers can get back the old behaviour of calling ->detect
every time probe_single_connector is called from userspace. I've splattered that
over all drivers where I've thought it might be required.

Note though that setting this doesn't avoid all regressions - the regular output
poll work will still ignore any connectors with POLL_HPD set. If a driver/hw
with broken hpd got away due to this, this will break stuff. But that should be
easy to fix by admitting the defeat and setting POLL_CONNECT|DISCONNECT
directly.

If other people want to convert over their drivers, the following steps are
required:
- Ensure that the connector status is unknown every time the driver could have
  missed a hpd event (e.g. after resume). drm_mode_config_reset will do that for
  you.
- Drop the POLL_FORCE flag for connectors where hdp is fully reliable.
- Implement edid caching - that's a nice way to figure out whether hpd is
  actually reliable, because if it isn't, this step will ensure that you get bug
  reports because the the edid won't ever get updated ;-)
- Optionally teach the driver some smarts about which specific connectors
  actually got a hotplug event. Mostly useful on cheap hw (like intel's) that
  can't distinguish between hdmi and dp without trying some aux channel
  transfers.

As you can guess from the patch series, I've discovered the hard way that i915
sdvo support is totally broken. Tested on most of the intel machines I have and
also quickly on my radeon hd5000.

Comments, flames, ideas and test reports highly welcome.

Cheers, Daniel

Daniel Vetter (14):
  drm: extract drm_kms_helper_hotplug_event
  drm: handle HDP and polled connectors separately
  drm: introduce DRM_CONNECTOR_POLL_FORCE
  drm/i915: set POLL_FORCE for sdvo outputs
  drm: properly init/reset connector status
  drm: kill unnecessary calls to connector->detect
  drm: don't start the poll engine in probe_single_connector
  drm: don't unnecessarily enable the polling work
  drm: don't poll forced connectors
  drm/i915: cache crt edid
  drm/i915: cache dp edid
  drm/i915: cache hdmi edid
  drm/i915/sdvo: implement correct return value for ->get_modes
  drm/i915: s/mdelay/msleep/ in the sdvo detect function

 drivers/gpu/drm/drm_crtc.c                    |    6 ++-
 drivers/gpu/drm/drm_crtc_helper.c             |   76 ++++++++++++++++++-------
 drivers/gpu/drm/exynos/exynos_drm_connector.c |    2 +
 drivers/gpu/drm/gma500/cdv_intel_crt.c        |    2 +
 drivers/gpu/drm/gma500/cdv_intel_hdmi.c       |    2 +
 drivers/gpu/drm/gma500/mdfld_dsi_output.c     |    1 +
 drivers/gpu/drm/gma500/oaktrail_hdmi.c        |    2 +
 drivers/gpu/drm/gma500/psb_intel_sdvo.c       |    2 +
 drivers/gpu/drm/i915/intel_crt.c              |   28 +++++++--
 drivers/gpu/drm/i915/intel_dp.c               |   47 +++++++--------
 drivers/gpu/drm/i915/intel_drv.h              |    2 +
 drivers/gpu/drm/i915/intel_hdmi.c             |   48 ++++++++++------
 drivers/gpu/drm/i915/intel_modes.c            |   18 +++++-
 drivers/gpu/drm/i915/intel_sdvo.c             |   45 +++++++++------
 drivers/gpu/drm/i915/intel_tv.c               |    3 +-
 drivers/gpu/drm/nouveau/nouveau_connector.c   |    1 +
 drivers/gpu/drm/radeon/radeon_connectors.c    |    5 ++
 drivers/gpu/drm/udl/udl_connector.c           |    2 +
 drivers/staging/omapdrm/omap_connector.c      |    2 +
 include/drm/drm_crtc.h                        |    5 ++
 include/drm/drm_crtc_helper.h                 |    1 +
 21 files changed, 208 insertions(+), 92 deletions(-)

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1.7.7.6