linux-kernel - Re: [PATCH v3 2/4] drm_dp_mst_topology: use correct AUX channel

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Message-ID: <5f2e7207e5227bdeb3c8e8cf453757cfbb5a4344.camel@redhat.com>
Date:   Mon, 01 Feb 2021 16:58:25 -0500
From:   Lyude Paul <lyude@...hat.com>
To:     Sam McNally <sammc@...omium.org>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Hans Verkuil <hverkuil@...all.nl>,
        Hans Verkuil <hans.verkuil@...co.com>,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v3 2/4] drm_dp_mst_topology: use correct AUX channel

On Wed, 2020-09-23 at 12:13 +1000, Sam McNally wrote:
> From: Hans Verkuil <hans.verkuil@...co.com>
> 
> For adapters behind an MST hub use the correct AUX channel.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@...co.com>
> [sammc@...omium.org: rebased, removing redundant changes]
> Signed-off-by: Sam McNally <sammc@...omium.org>
> ---
> 
> (no changes since v1)
> 
>  drivers/gpu/drm/drm_dp_mst_topology.c | 36 +++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 15b6cc39a754..0d753201adbd 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -2255,6 +2255,9 @@ drm_dp_mst_topology_unlink_port(struct
> drm_dp_mst_topology_mgr *mgr,
>         drm_dp_mst_topology_put_port(port);
>  }
>  
> +static ssize_t
> +drm_dp_mst_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg);
> +
>  static struct drm_dp_mst_port *
>  drm_dp_mst_add_port(struct drm_device *dev,
>                     struct drm_dp_mst_topology_mgr *mgr,
> @@ -2271,9 +2274,13 @@ drm_dp_mst_add_port(struct drm_device *dev,
>         port->port_num = port_number;
>         port->mgr = mgr;
>         port->aux.name = "DPMST";
> +       mutex_init(&port->aux.hw_mutex);
> +       mutex_init(&port->aux.cec.lock);

You're missing a matching mutex_destroy() for both of these

With that fixed:

Reviewed-by: Lyude Paul <lyude@...hat.com>

>         port->aux.dev = dev->dev;
>         port->aux.is_remote = true;
>  
> +       port->aux.transfer = drm_dp_mst_aux_transfer;
> +
>         /* initialize the MST downstream port's AUX crc work queue */
>         drm_dp_remote_aux_init(&port->aux);
>  
> @@ -3503,6 +3510,35 @@ static int drm_dp_send_up_ack_reply(struct
> drm_dp_mst_topology_mgr *mgr,
>         return 0;
>  }
>  
> +static ssize_t
> +drm_dp_mst_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
> +{
> +       struct drm_dp_mst_port *port =
> +               container_of(aux, struct drm_dp_mst_port, aux);
> +       int ret;
> +
> +       switch (msg->request & ~DP_AUX_I2C_MOT) {
> +       case DP_AUX_NATIVE_WRITE:
> +       case DP_AUX_I2C_WRITE:
> +       case DP_AUX_I2C_WRITE_STATUS_UPDATE:
> +               ret = drm_dp_send_dpcd_write(port->mgr, port, msg->address,
> +                                            msg->size, msg->buffer);
> +               break;
> +
> +       case DP_AUX_NATIVE_READ:
> +       case DP_AUX_I2C_READ:
> +               ret = drm_dp_send_dpcd_read(port->mgr, port, msg->address,
> +                                           msg->size, msg->buffer);
> +               break;
> +
> +       default:
> +               ret = -EINVAL;
> +               break;
> +       }
> +
> +       return ret;
> +}
> +
>  static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8  dp_link_count)
>  {
>         if (dp_link_bw == 0 || dp_link_count == 0)

-- 
Sincerely,
   Lyude Paul (she/her)
   Software Engineer at Red Hat
   
Note: I deal with a lot of emails and have a lot of bugs on my plate. If you've
asked me a question, are waiting for a review/merge on a patch, etc. and I
haven't responded in a while, please feel free to send me another email to check
on my status. I don't bite!