Re: [PATCH 1/2] drm/radeon: Poll for both connect/disconnect on analog connectors

[Lyude]

Whoops, very sorry about this! I ran git send-email, and it looks like
I had forgotten to remove some other patches in my patches/ folder.
Going to resend this to avoid confusing anyone trying to review this.

On Fri, 2016-06-24 at 17:45 -0400, Lyude wrote:
> DRM_CONNECTOR_POLL_CONNECT only enables polling for connections, not
> disconnections. Because of this, we end up losing hotplug polling for
> analog connectors once they get connected.
> 
> Easy way to reproduce:
> Â- Grab a machine with a radeon GPU and a VGA port
> Â- Plug a monitor into the VGA port, wait for it to update the
> connector
> ÂÂÂfrom disconnected to connected
> Â- Disconnect the monitor on VGA, a hotplug event is never sent for
> the
> ÂÂÂremoval of the connector.
> 
> Originally, only using DRM_CONNECTOR_POLL_CONNECT might have been a
> good
> idea since doing VGA polling can sometimes result in having to mess
> with
> the DAC voltages to figure out whether or not there's actually
> something
> there since VGA doesn't have HPD. Doing this would have the potential
> of
> showing visible artifacts on the screen every time we ran a poll
> while a
> VGA display was connected. Luckily, radeon_vga_detect() only resorts
> to
> this sort of polling if the poll is forced, and DRM's polling helper
> doesn't force it's polls.
> 
> Additionally, this removes some assignments to connector->polled that
> weren't actually doing anything.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Lyude <cpaul@xxxxxxxxxx>
> ---
> Âdrivers/gpu/drm/radeon/radeon_connectors.c | 15 +++++++++------
> Â1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c
> b/drivers/gpu/drm/radeon/radeon_connectors.c
> index 81a63d7..b79f3b0 100644
> --- a/drivers/gpu/drm/radeon/radeon_connectors.c
> +++ b/drivers/gpu/drm/radeon/radeon_connectors.c
> @@ -2064,7 +2064,6 @@ radeon_add_atom_connector(struct drm_device
> *dev,
> Â							ÂÂÂRADEON_OU
> TPUT_CSC_BYPASS);
> Â			/* no HPD on analog connectors */
> Â			radeon_connector->hpd.hpd = RADEON_HPD_NONE;
> -			connector->polled =
> DRM_CONNECTOR_POLL_CONNECT;
> Â			connector->interlace_allowed = true;
> Â			connector->doublescan_allowed = true;
> Â			break;
> @@ -2314,8 +2313,10 @@ radeon_add_atom_connector(struct drm_device
> *dev,
> Â	}
> Â
> Â	if (radeon_connector->hpd.hpd == RADEON_HPD_NONE) {
> -		if (i2c_bus->valid)
> -			connector->polled =
> DRM_CONNECTOR_POLL_CONNECT;
> +		if (i2c_bus->valid) {
> +			connector->polled =
> DRM_CONNECTOR_POLL_CONNECT |
> +			ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂDRM_CONNECTOR_POLL_DISCO
> NNECT;
> +		}
> Â	} else
> Â		connector->polled = DRM_CONNECTOR_POLL_HPD;
> Â
> @@ -2391,7 +2392,6 @@ radeon_add_legacy_connector(struct drm_device
> *dev,
> Â					ÂÂÂÂÂÂ1);
> Â		/* no HPD on analog connectors */
> Â		radeon_connector->hpd.hpd = RADEON_HPD_NONE;
> -		connector->polled = DRM_CONNECTOR_POLL_CONNECT;
> Â		connector->interlace_allowed = true;
> Â		connector->doublescan_allowed = true;
> Â		break;
> @@ -2476,10 +2476,13 @@ radeon_add_legacy_connector(struct drm_device
> *dev,
> Â	}
> Â
> Â	if (radeon_connector->hpd.hpd == RADEON_HPD_NONE) {
> -		if (i2c_bus->valid)
> -			connector->polled =
> DRM_CONNECTOR_POLL_CONNECT;
> +		if (i2c_bus->valid) {
> +			connector->polled =
> DRM_CONNECTOR_POLL_CONNECT |
> +			ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂDRM_CONNECTOR_POLL_DISCO
> NNECT;
> +		}
> Â	} else
> Â		connector->polled = DRM_CONNECTOR_POLL_HPD;
> +
> Â	connector->display_info.subpixel_order = subpixel_order;
> Â	drm_connector_register(connector);
> Â}
-- 

Cheers,
	Lyude