[Freedreno] [PATCH v3 0/7] drm/bridge_connector: perform HPD enablement automatically

[Laurentiu Palcu]

Hi Dmitry,

It looks like there are some issues with this patchset... :/ I just
fetched the drm-tip and, with these patches included, the "Hot plug
detection already enabled" warning is back for i.MX DCSS.

After a short investigation, it seems that we end up calling
drm_bridge_hpd_enable() from both drm_kms_helper_poll_init() and
drm_fbdev_generic_setup(), hence the warning.

There are drivers using the drm_bridge_connector API that also call
drm_kms_helper_poll_init() followed by drm_fbdev_generic_setup(). So,
they might experience the same behavior, unless I'm missing something...
:/

Also, even if drm_fbdev_generic_setup() is not called in the driver
initialization, the warning will still appear the first time the
GETCONNECTOR ioctl is called, because that'll call
drm_helper_probe_single_connector_modes() helper which will eventually
call drm_bridge_hpd_enable().

Any idea?

Cheers,
Laurentiu

On Wed, Nov 02, 2022 at 09:06:58PM +0300, Dmitry Baryshkov wrote:
> From all the drivers using drm_bridge_connector only iMX/dcss and OMAP
> DRM driver do a proper work of calling
> drm_bridge_connector_en/disable_hpd() in right places. Rather than
> teaching each and every driver how to properly handle
> drm_bridge_connector's HPD, make that automatic.
> 
> Add two additional drm_connector helper funcs: enable_hpd() and
> disable_hpd(). Make drm_kms_helper_poll_* functions call them (as this
> is the time where the drm_bridge_connector's functions are called by the
> drivers too).
> 
> Changes since v2:
>  - Fixed a typo in the commit message of the second patch.
> 
> Changes since v1:
>  - Rebased on top of v6.1-rc1
>  - Removed the drm_bridge_connector_enable_hpd() from
>    drm_bridge_connector_init()
>  - Removed extra underscore prefix from
>    drm_bridge_connector_en/disable_hpd() helpers
> 
> Dmitry Baryshkov (7):
>   drm/poll-helper: merge drm_kms_helper_poll_disable() and _fini()
>   drm/probe-helper: enable and disable HPD on connectors
>   drm/bridge_connector: rely on drm_kms_helper_poll_* for HPD enablement
>   drm/imx/dcss: stop using drm_bridge_connector_en/disable_hpd()
>   drm/msm/hdmi: stop using drm_bridge_connector_en/disable_hpd()
>   drm/omap: stop using drm_bridge_connector_en/disable_hpd()
>   drm/bridge_connector: drop drm_bridge_connector_en/disable_hpd()
> 
>  drivers/gpu/drm/drm_bridge_connector.c   | 27 +++-------------
>  drivers/gpu/drm/drm_probe_helper.c       | 40 ++++++++++++++++++-----
>  drivers/gpu/drm/imx/dcss/dcss-dev.c      |  4 ---
>  drivers/gpu/drm/imx/dcss/dcss-kms.c      |  2 --
>  drivers/gpu/drm/msm/hdmi/hdmi.c          |  2 --
>  drivers/gpu/drm/omapdrm/omap_drv.c       | 41 ------------------------
>  include/drm/drm_bridge_connector.h       |  2 --
>  include/drm/drm_modeset_helper_vtables.h | 22 +++++++++++++
>  8 files changed, 59 insertions(+), 81 deletions(-)
> 
> -- 
> 2.35.1
>