Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2
3#include <linux/string.h>
4
5#include <drm/drm_drv.h>
6#include <drm/drm_edid.h>
7#include <drm/drm_print.h>
8
9#include "udl_drv.h"
10#include "udl_edid.h"
11
12static int udl_read_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
13{
14 struct udl_device *udl = data;
15 struct drm_device *dev = &udl->drm;
16 struct usb_device *udev = udl_to_usb_device(udl);
17 u8 *read_buff;
18 int idx, ret;
19 size_t i;
20
21 read_buff = kmalloc(2, GFP_KERNEL);
22 if (!read_buff)
23 return -ENOMEM;
24
25 if (!drm_dev_enter(dev, &idx)) {
26 ret = -ENODEV;
27 goto err_kfree;
28 }
29
30 for (i = 0; i < len; i++) {
31 int bval = (i + block * EDID_LENGTH) << 8;
32
33 ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
34 0x02, (0x80 | (0x02 << 5)), bval,
35 0xA1, read_buff, 2, USB_CTRL_GET_TIMEOUT);
36 if (ret < 0) {
37 drm_err(dev, "Read EDID byte %zu failed err %x\n", i, ret);
38 goto err_drm_dev_exit;
39 } else if (ret < 1) {
40 ret = -EIO;
41 drm_err(dev, "Read EDID byte %zu failed\n", i);
42 goto err_drm_dev_exit;
43 }
44
45 buf[i] = read_buff[1];
46 }
47
48 drm_dev_exit(idx);
49 kfree(read_buff);
50
51 return 0;
52
53err_drm_dev_exit:
54 drm_dev_exit(idx);
55err_kfree:
56 kfree(read_buff);
57 return ret;
58}
59
60bool udl_probe_edid(struct udl_device *udl)
61{
62 u8 hdr[8];
63 int ret;
64
65 ret = udl_read_edid_block(udl, hdr, 0, sizeof(hdr));
66 if (ret)
67 return false;
68
69 /*
70 * The adapter sends all-zeros if no monitor has been
71 * connected. We consider anything else a connection.
72 */
73 return !mem_is_zero(hdr, sizeof(hdr));
74}
75
76const struct drm_edid *udl_edid_read(struct drm_connector *connector)
77{
78 struct udl_device *udl = to_udl(connector->dev);
79
80 return drm_edid_read_custom(connector, udl_read_edid_block, udl);
81}