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// SPDX-License-Identifier: GPL-2.0-only
#include <linux/string.h>
#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)
{
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 !mem_is_zero(hdr, sizeof(hdr));
}
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);
}
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