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

[Alex Deucher]

On Thu, May 24, 2012 at 3:26 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> 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.

This set looks good to me.  Do you have plans to revive this?  At
least the common drm ones are much better than what we currently have.

Alex


>
> 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(-)
>
> --
> 1.7.7.6
>
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