81 lines
1.6 KiB
C
81 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/string.h>
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#include <drm/drm_drv.h>
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#include <drm/drm_edid.h>
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#include "udl_drv.h"
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#include "udl_edid.h"
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static int udl_read_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
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{
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struct udl_device *udl = data;
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struct drm_device *dev = &udl->drm;
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struct usb_device *udev = udl_to_usb_device(udl);
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u8 *read_buff;
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int idx, ret;
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size_t i;
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read_buff = kmalloc(2, GFP_KERNEL);
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if (!read_buff)
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return -ENOMEM;
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if (!drm_dev_enter(dev, &idx)) {
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ret = -ENODEV;
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goto err_kfree;
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}
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for (i = 0; i < len; i++) {
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int bval = (i + block * EDID_LENGTH) << 8;
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ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
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0x02, (0x80 | (0x02 << 5)), bval,
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0xA1, read_buff, 2, USB_CTRL_GET_TIMEOUT);
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if (ret < 0) {
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drm_err(dev, "Read EDID byte %zu failed err %x\n", i, ret);
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goto err_drm_dev_exit;
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} else if (ret < 1) {
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ret = -EIO;
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drm_err(dev, "Read EDID byte %zu failed\n", i);
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goto err_drm_dev_exit;
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}
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buf[i] = read_buff[1];
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}
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drm_dev_exit(idx);
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kfree(read_buff);
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return 0;
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err_drm_dev_exit:
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drm_dev_exit(idx);
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err_kfree:
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kfree(read_buff);
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return ret;
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}
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bool udl_probe_edid(struct udl_device *udl)
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{
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u8 hdr[8];
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int ret;
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ret = udl_read_edid_block(udl, hdr, 0, sizeof(hdr));
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if (ret)
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return false;
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/*
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* The adapter sends all-zeros if no monitor has been
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* connected. We consider anything else a connection.
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*/
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return !mem_is_zero(hdr, sizeof(hdr));
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}
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const struct drm_edid *udl_edid_read(struct drm_connector *connector)
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{
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struct udl_device *udl = to_udl(connector->dev);
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return drm_edid_read_custom(connector, udl_read_edid_block, udl);
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}
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