[PATCH] drm/udl: Fixed problem with UDL adpater reconnection

Alex Deucher alexdeucher at gmail.com
Thu Oct 12 19:56:13 UTC 2017


On Wed, Oct 11, 2017 at 4:41 PM, Robert Tarasov
<tutankhamen at chromium.org> wrote:
> Fixed problem with DisplayLink and DisplayLink certified adapters when they
> didn't want to work if they were initialized with disconnected DVI cable. Now
> udl driver checks and updates adapter's connection state every 10 seconds, as
> well as retreives all the edid data blocks instead of only base one. Previous
> approch could lead to improper initialization of video mode with certain
> monitors.
>

Seems like this should be split into two patches:

1. rework the EDID handling in the driver
2. enable drm connector polling.

Alex

> Signed-off-by: Robert Tarasov <tutankhamen at chromium.org>
> ---
>  drivers/gpu/drm/udl/udl_connector.c | 153 ++++++++++++++++++++++++------------
>  drivers/gpu/drm/udl/udl_connector.h |  13 +++
>  drivers/gpu/drm/udl/udl_drv.c       |   4 +
>  drivers/gpu/drm/udl/udl_main.c      |   5 ++
>  4 files changed, 125 insertions(+), 50 deletions(-)
>  create mode 100644 drivers/gpu/drm/udl/udl_connector.h
>
> diff --git a/drivers/gpu/drm/udl/udl_connector.c b/drivers/gpu/drm/udl/udl_connector.c
> index 9f9a49748d17..b2d9ffcc29aa 100644
> --- a/drivers/gpu/drm/udl/udl_connector.c
> +++ b/drivers/gpu/drm/udl/udl_connector.c
> @@ -14,70 +14,95 @@
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_edid.h>
>  #include <drm/drm_crtc_helper.h>
> +#include "udl_connector.h"
>  #include "udl_drv.h"
>
> -/* dummy connector to just get EDID,
> -   all UDL appear to have a DVI-D */
> -
> -static u8 *udl_get_edid(struct udl_device *udl)
> +static bool udl_get_edid_block(struct udl_device *udl, int block_idx,
> +                                                          u8 *buff)
>  {
> -       u8 *block;
> -       char *rbuf;
>         int ret, i;
> +       u8 *read_buff;
>
> -       block = kmalloc(EDID_LENGTH, GFP_KERNEL);
> -       if (block == NULL)
> -               return NULL;
> -
> -       rbuf = kmalloc(2, GFP_KERNEL);
> -       if (rbuf == NULL)
> -               goto error;
> +       read_buff = kmalloc(2, GFP_KERNEL);
> +       if (!read_buff)
> +               return false;
>
>         for (i = 0; i < EDID_LENGTH; i++) {
> +               int bval = (i + block_idx * EDID_LENGTH) << 8;
>                 ret = usb_control_msg(udl->udev,
> -                                     usb_rcvctrlpipe(udl->udev, 0), (0x02),
> -                                     (0x80 | (0x02 << 5)), i << 8, 0xA1, rbuf, 2,
> -                                     HZ);
> +                                     usb_rcvctrlpipe(udl->udev, 0),
> +                                         (0x02), (0x80 | (0x02 << 5)), bval,
> +                                         0xA1, read_buff, 2, HZ);
>                 if (ret < 1) {
>                         DRM_ERROR("Read EDID byte %d failed err %x\n", i, ret);
> -                       goto error;
> +                       kfree(read_buff);
> +                       return false;
>                 }
> -               block[i] = rbuf[1];
> +               buff[i] = read_buff[1];
>         }
>
> -       kfree(rbuf);
> -       return block;
> -
> -error:
> -       kfree(block);
> -       kfree(rbuf);
> -       return NULL;
> +       kfree(read_buff);
> +       return true;
>  }
>
> -static int udl_get_modes(struct drm_connector *connector)
> +static bool udl_get_edid(struct udl_device *udl, u8 **result_buff,
> +                        int *result_buff_size)
>  {
> -       struct udl_device *udl = connector->dev->dev_private;
> -       struct edid *edid;
> -       int ret;
> -
> -       edid = (struct edid *)udl_get_edid(udl);
> -       if (!edid) {
> -               drm_mode_connector_update_edid_property(connector, NULL);
> -               return 0;
> +       int i, extensions;
> +       u8 *block_buff = NULL, *buff_ptr;
> +
> +       block_buff = kmalloc(EDID_LENGTH, GFP_KERNEL);
> +       if (block_buff == NULL)
> +               return false;
> +
> +       if (udl_get_edid_block(udl, 0, block_buff) &&
> +           memchr_inv(block_buff, 0, EDID_LENGTH)) {
> +               extensions = ((struct edid *)block_buff)->extensions;
> +               if (extensions > 0) {
> +                       /* we have to read all extensions one by one */
> +                       *result_buff_size = EDID_LENGTH * (extensions + 1);
> +                       *result_buff = kmalloc(*result_buff_size, GFP_KERNEL);
> +                       buff_ptr = *result_buff;
> +                       if (buff_ptr == NULL) {
> +                               kfree(block_buff);
> +                               return false;
> +                       }
> +                       memcpy(buff_ptr, block_buff, EDID_LENGTH);
> +                       kfree(block_buff);
> +                       buff_ptr += EDID_LENGTH;
> +                       for (i = 1; i < extensions; ++i) {
> +                               if (udl_get_edid_block(udl, i, buff_ptr)) {
> +                                       buff_ptr += EDID_LENGTH;
> +                               } else {
> +                                       kfree(*result_buff);
> +                                       *result_buff = NULL;
> +                                       return false;
> +                               }
> +                       }
> +                       return true;
> +               }
> +               /* we have only base edid block */
> +               *result_buff = block_buff;
> +               *result_buff_size = EDID_LENGTH;
> +               return true;
>         }
>
> -       /*
> -        * We only read the main block, but if the monitor reports extension
> -        * blocks then the drm edid code expects them to be present, so patch
> -        * the extension count to 0.
> -        */
> -       edid->checksum += edid->extensions;
> -       edid->extensions = 0;
> -
> -       drm_mode_connector_update_edid_property(connector, edid);
> -       ret = drm_add_edid_modes(connector, edid);
> -       kfree(edid);
> -       return ret;
> +       kfree(block_buff);
> +
> +       return false;
> +}
> +
> +static int udl_get_modes(struct drm_connector *connector)
> +{
> +       struct udl_drm_connector *udl_connector =
> +                                       container_of(connector,
> +                                       struct udl_drm_connector,
> +                                       connector);
> +
> +       drm_mode_connector_update_edid_property(connector, udl_connector->edid);
> +       if (udl_connector->edid)
> +               return drm_add_edid_modes(connector, udl_connector->edid);
> +       return 0;
>  }
>
>  static int udl_mode_valid(struct drm_connector *connector,
> @@ -96,8 +121,25 @@ static int udl_mode_valid(struct drm_connector *connector,
>  static enum drm_connector_status
>  udl_detect(struct drm_connector *connector, bool force)
>  {
> -       if (drm_dev_is_unplugged(connector->dev))
> +       u8 *edid_buff = NULL;
> +       int edid_buff_size = 0;
> +       struct udl_device *udl = connector->dev->dev_private;
> +       struct udl_drm_connector *udl_connector =
> +                                       container_of(connector,
> +                                       struct udl_drm_connector,
> +                                       connector);
> +
> +       /* cleanup previous edid */
> +       if (udl_connector->edid != NULL) {
> +               kfree(udl_connector->edid);
> +               udl_connector->edid = NULL;
> +       }
> +
> +       if (!udl_get_edid(udl, &edid_buff, &edid_buff_size))
>                 return connector_status_disconnected;
> +
> +       udl_connector->edid = (struct edid *)edid_buff;
> +
>         return connector_status_connected;
>  }
>
> @@ -117,8 +159,14 @@ static int udl_connector_set_property(struct drm_connector *connector,
>
>  static void udl_connector_destroy(struct drm_connector *connector)
>  {
> +       struct udl_drm_connector *udl_connector =
> +                                       container_of(connector,
> +                                       struct udl_drm_connector,
> +                                       connector);
> +
>         drm_connector_unregister(connector);
>         drm_connector_cleanup(connector);
> +       kfree(udl_connector->edid);
>         kfree(connector);
>  }
>
> @@ -138,17 +186,22 @@ static const struct drm_connector_funcs udl_connector_funcs = {
>
>  int udl_connector_init(struct drm_device *dev, struct drm_encoder *encoder)
>  {
> +       struct udl_drm_connector *udl_connector;
>         struct drm_connector *connector;
>
> -       connector = kzalloc(sizeof(struct drm_connector), GFP_KERNEL);
> -       if (!connector)
> +       udl_connector = kzalloc(sizeof(struct udl_drm_connector), GFP_KERNEL);
> +       if (!udl_connector)
>                 return -ENOMEM;
>
> -       drm_connector_init(dev, connector, &udl_connector_funcs, DRM_MODE_CONNECTOR_DVII);
> +       connector = &udl_connector->connector;
> +       drm_connector_init(dev, connector, &udl_connector_funcs,
> +                          DRM_MODE_CONNECTOR_DVII);
>         drm_connector_helper_add(connector, &udl_connector_helper_funcs);
>
>         drm_connector_register(connector);
>         drm_mode_connector_attach_encoder(connector, encoder);
> +       connector->polled = DRM_CONNECTOR_POLL_HPD |
> +               DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;
>
>         return 0;
>  }
> diff --git a/drivers/gpu/drm/udl/udl_connector.h b/drivers/gpu/drm/udl/udl_connector.h
> new file mode 100644
> index 000000000000..0fb0db5c4612
> --- /dev/null
> +++ b/drivers/gpu/drm/udl/udl_connector.h
> @@ -0,0 +1,13 @@
> +#ifndef __UDL_CONNECTOR_H__
> +#define __UDL_CONNECTOR_H__
> +
> +#include <drm/drm_crtc.h>
> +
> +struct udl_drm_connector {
> +       struct drm_connector connector;
> +       /* last udl_detect edid */
> +       struct edid *edid;
> +};
> +
> +
> +#endif //__UDL_CONNECTOR_H__
> diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c
> index 31421b6b586e..3c45a3064726 100644
> --- a/drivers/gpu/drm/udl/udl_drv.c
> +++ b/drivers/gpu/drm/udl/udl_drv.c
> @@ -14,6 +14,9 @@
>  static int udl_usb_suspend(struct usb_interface *interface,
>                            pm_message_t message)
>  {
> +       struct drm_device *dev = usb_get_intfdata(interface);
> +
> +       drm_kms_helper_poll_disable(dev);
>         return 0;
>  }
>
> @@ -21,6 +24,7 @@ static int udl_usb_resume(struct usb_interface *interface)
>  {
>         struct drm_device *dev = usb_get_intfdata(interface);
>
> +       drm_kms_helper_poll_enable(dev);
>         udl_modeset_restore(dev);
>         return 0;
>  }
> diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
> index 0328b2c7b210..f1ec4528a73e 100644
> --- a/drivers/gpu/drm/udl/udl_main.c
> +++ b/drivers/gpu/drm/udl/udl_main.c
> @@ -11,6 +11,7 @@
>   * more details.
>   */
>  #include <drm/drmP.h>
> +#include <drm/drm_crtc_helper.h>
>  #include "udl_drv.h"
>
>  /* -BULK_SIZE as per usb-skeleton. Can we get full page and avoid overhead? */
> @@ -350,6 +351,8 @@ int udl_driver_load(struct drm_device *dev, unsigned long flags)
>         if (ret)
>                 goto err_fb;
>
> +       drm_kms_helper_poll_init(dev);
> +
>         return 0;
>  err_fb:
>         udl_fbdev_cleanup(dev);
> @@ -371,6 +374,8 @@ void udl_driver_unload(struct drm_device *dev)
>  {
>         struct udl_device *udl = dev->dev_private;
>
> +       drm_kms_helper_poll_fini(dev);
> +
>         if (udl->urbs.count)
>                 udl_free_urb_list(dev);
>
> --
> 2.15.0.rc0.271.g36b669edcc-goog
>
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