On Wed, 10 Apr 2024, Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
> Provide separate implementations of .get_modes() and .detect_ctx()
> from struct drm_connector. Switch to struct drm_edid.
>
> Udl's .detect() helper used to fetch the EDID from the adapter and the
> .get_modes() helper provided display modes from the data. But this
> relied on the DRM helpers to call the functions in the correct order.
> When no EDID could be retrieved, .detect() regularly printed a warning
> to the kernel log.
>
> Switching to the new helpers around struct drm_edid separates both from
> each other. The .get_modes() helper now fetches the EDID by itself and
> the .detect_ctx() helper only tests for its presence. The patch does a
> number of things to implement this.
>
> - Move udl_get_edid_block() to udl_edid.c and rename it to
> udl_read_edid_block(). Then use the helper to implement probing in
> udl_probe_edid() and reading in udl_edid_read(). The latter helper
> is build on top of DRM helpers.
>
> - Replace the existing code in .get_modes() and .detect() with udl's
> new EDID helpers. The new code behaves like DRM's similar DDC-based
> helpers. Instead of .detect(), udl now implements .detect_ctx().
>
> - Remove the edid data from struct udl_connector. The field cached
> the EDID data between calls to .detect() and .get_modes(), but is now
> unused.
>
> v2:
> - implement udl_probe_edid() within udl
> - reword commit description
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> ---
> drivers/gpu/drm/udl/Makefile | 1 +
> drivers/gpu/drm/udl/udl_drv.h | 2 -
> drivers/gpu/drm/udl/udl_edid.c | 79 +++++++++++++++++++++++++++
> drivers/gpu/drm/udl/udl_edid.h | 15 ++++++
> drivers/gpu/drm/udl/udl_modeset.c | 90 +++++++------------------------
> 5 files changed, 114 insertions(+), 73 deletions(-)
> create mode 100644 drivers/gpu/drm/udl/udl_edid.c
> create mode 100644 drivers/gpu/drm/udl/udl_edid.h
>
> diff --git a/drivers/gpu/drm/udl/Makefile b/drivers/gpu/drm/udl/Makefile
> index 00690741db376..43d69a16af183 100644
> --- a/drivers/gpu/drm/udl/Makefile
> +++ b/drivers/gpu/drm/udl/Makefile
> @@ -2,6 +2,7 @@
>
> udl-y := \
> udl_drv.o \
> + udl_edid.o \
> udl_main.o \
> udl_modeset.o \
> udl_transfer.o
> diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
> index 282ebd6c02fda..f112cfb270f31 100644
> --- a/drivers/gpu/drm/udl/udl_drv.h
> +++ b/drivers/gpu/drm/udl/udl_drv.h
> @@ -51,8 +51,6 @@ struct urb_list {
>
> struct udl_connector {
> struct drm_connector connector;
> - /* last udl_detect edid */
> - struct edid *edid;
> };
>
> static inline struct udl_connector *to_udl_connector(struct drm_connector *connector)
> diff --git a/drivers/gpu/drm/udl/udl_edid.c b/drivers/gpu/drm/udl/udl_edid.c
> new file mode 100644
> index 0000000000000..626f1badea90a
> --- /dev/null
> +++ b/drivers/gpu/drm/udl/udl_edid.c
> @@ -0,0 +1,79 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <drm/drm_drv.h>
> +#include <drm/drm_edid.h>
> +
> +#include "udl_drv.h"
> +#include "udl_edid.h"
> +
> +static int udl_read_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
> +{
> + struct udl_device *udl = data;
> + struct drm_device *dev = &udl->drm;
> + struct usb_device *udev = udl_to_usb_device(udl);
> + u8 *read_buff;
> + int idx, ret;
> + size_t i;
> +
> + read_buff = kmalloc(2, GFP_KERNEL);
> + if (!read_buff)
> + return -ENOMEM;
> +
> + if (!drm_dev_enter(dev, &idx)) {
> + ret = -ENODEV;
> + goto err_kfree;
> + }
> +
> + for (i = 0; i < len; i++) {
> + int bval = (i + block * EDID_LENGTH) << 8;
> +
> + ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
> + 0x02, (0x80 | (0x02 << 5)), bval,
> + 0xA1, read_buff, 2, USB_CTRL_GET_TIMEOUT);
> + if (ret < 0) {
> + drm_err(dev, "Read EDID byte %zu failed err %x\n", i, ret);
> + goto err_drm_dev_exit;
> + } else if (ret < 1) {
> + ret = -EIO;
> + drm_err(dev, "Read EDID byte %zu failed\n", i);
> + goto err_drm_dev_exit;
> + }
> +
> + buf[i] = read_buff[1];
> + }
> +
> + drm_dev_exit(idx);
> + kfree(read_buff);
> +
> + return 0;
> +
> +err_drm_dev_exit:
> + drm_dev_exit(idx);
> +err_kfree:
> + kfree(read_buff);
> + return ret;
> +}
> +
> +bool udl_probe_edid(struct udl_device *udl)
> +{
> + static const u8 no_edid[8] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
> + u8 hdr[8];
> + int ret;
> +
> + ret = udl_read_edid_block(udl, hdr, 0, sizeof(hdr));
> + if (ret)
> + return false;
> +
> + /*
> + * The adapter sends all-zeros if no monitor has been
> + * connected. We consider anything else a connection.
> + */
> + return memcmp(no_edid, hdr, 8) != 0;
Nitpick, this works, but you can drop the no_edid buf by using:
return memchr_inv(hdr, 0, sizeof(hdr));
Up to you,
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> +}
> +
> +const struct drm_edid *udl_edid_read(struct drm_connector *connector)
> +{
> + struct udl_device *udl = to_udl(connector->dev);
> +
> + return drm_edid_read_custom(connector, udl_read_edid_block, udl);
> +}
> diff --git a/drivers/gpu/drm/udl/udl_edid.h b/drivers/gpu/drm/udl/udl_edid.h
> new file mode 100644
> index 0000000000000..fe15ff3752b7d
> --- /dev/null
> +++ b/drivers/gpu/drm/udl/udl_edid.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#ifndef UDL_EDID_H
> +#define UDL_EDID_H
> +
> +#include <linux/types.h>
> +
> +struct drm_connector;
> +struct drm_edid;
> +struct udl_device;
> +
> +bool udl_probe_edid(struct udl_device *udl);
> +const struct drm_edid *udl_edid_read(struct drm_connector *connector);
> +
> +#endif
> diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
> index 3df9fc38388b4..4236ce57f5945 100644
> --- a/drivers/gpu/drm/udl/udl_modeset.c
> +++ b/drivers/gpu/drm/udl/udl_modeset.c
> @@ -25,6 +25,7 @@
> #include <drm/drm_vblank.h>
>
> #include "udl_drv.h"
> +#include "udl_edid.h"
> #include "udl_proto.h"
>
> /*
> @@ -415,97 +416,44 @@ static const struct drm_encoder_funcs udl_encoder_funcs = {
>
> static int udl_connector_helper_get_modes(struct drm_connector *connector)
> {
> - struct udl_connector *udl_connector = to_udl_connector(connector);
> + const struct drm_edid *drm_edid;
> + int count;
>
> - drm_connector_update_edid_property(connector, udl_connector->edid);
> - if (udl_connector->edid)
> - return drm_add_edid_modes(connector, udl_connector->edid);
> + drm_edid = udl_edid_read(connector);
> + drm_edid_connector_update(connector, drm_edid);
> + count = drm_edid_connector_add_modes(connector);
> + drm_edid_free(drm_edid);
>
> - return 0;
> + return count;
> }
>
> -static const struct drm_connector_helper_funcs udl_connector_helper_funcs = {
> - .get_modes = udl_connector_helper_get_modes,
> -};
> -
> -static int udl_get_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
> +static int udl_connector_helper_detect_ctx(struct drm_connector *connector,
> + struct drm_modeset_acquire_ctx *ctx,
> + bool force)
> {
> - struct udl_device *udl = data;
> - struct drm_device *dev = &udl->drm;
> - struct usb_device *udev = udl_to_usb_device(udl);
> - u8 *read_buff;
> - int idx, ret;
> - size_t i;
> -
> - read_buff = kmalloc(2, GFP_KERNEL);
> - if (!read_buff)
> - return -ENOMEM;
> + struct udl_device *udl = to_udl(connector->dev);
>
> - if (!drm_dev_enter(dev, &idx)) {
> - ret = -ENODEV;
> - goto err_kfree;
> - }
> -
> - for (i = 0; i < len; i++) {
> - int bval = (i + block * EDID_LENGTH) << 8;
> -
> - ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
> - 0x02, (0x80 | (0x02 << 5)), bval,
> - 0xA1, read_buff, 2, USB_CTRL_GET_TIMEOUT);
> - if (ret < 0) {
> - drm_err(dev, "Read EDID byte %zu failed err %x\n", i, ret);
> - goto err_drm_dev_exit;
> - } else if (ret < 1) {
> - ret = -EIO;
> - drm_err(dev, "Read EDID byte %zu failed\n", i);
> - goto err_drm_dev_exit;
> - }
> -
> - buf[i] = read_buff[1];
> - }
> + if (udl_probe_edid(udl))
> + return connector_status_connected;
>
> - drm_dev_exit(idx);
> - kfree(read_buff);
> -
> - return 0;
> -
> -err_drm_dev_exit:
> - drm_dev_exit(idx);
> -err_kfree:
> - kfree(read_buff);
> - return ret;
> + return connector_status_disconnected;
> }
>
> -static enum drm_connector_status udl_connector_detect(struct drm_connector *connector, bool force)
> -{
> - struct drm_device *dev = connector->dev;
> - struct udl_device *udl = to_udl(dev);
> - struct udl_connector *udl_connector = to_udl_connector(connector);
> - enum drm_connector_status status = connector_status_disconnected;
> -
> - /* cleanup previous EDID */
> - kfree(udl_connector->edid);
> - udl_connector->edid = NULL;
> -
> - udl_connector->edid = drm_do_get_edid(connector, udl_get_edid_block, udl);
> - if (udl_connector->edid)
> - status = connector_status_connected;
> -
> - return status;
> -}
> +static const struct drm_connector_helper_funcs udl_connector_helper_funcs = {
> + .get_modes = udl_connector_helper_get_modes,
> + .detect_ctx = udl_connector_helper_detect_ctx,
> +};
>
> static void udl_connector_destroy(struct drm_connector *connector)
> {
> struct udl_connector *udl_connector = to_udl_connector(connector);
>
> drm_connector_cleanup(connector);
> - kfree(udl_connector->edid);
> kfree(udl_connector);
> }
>
> static const struct drm_connector_funcs udl_connector_funcs = {
> .reset = drm_atomic_helper_connector_reset,
> - .detect = udl_connector_detect,
> .fill_modes = drm_helper_probe_single_connector_modes,
> .destroy = udl_connector_destroy,
> .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
--
Jani Nikula, Intel
