drm/udl: Remove field lost_pixels from struct udl_device

The field lost_pixels in struct udl_device was supposed to signal an
error during USB transfers of the framebuffer data. The driver would
have to schedule a re-transfer at a later point. This code was never
implemented. Remove lost_pixels and return regular error codes instead.

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Emil Velikov <[e-mail]>
Acked-by: Gerd Hoffmann <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/udl/udl_drv.h

···
 	int sku_pixel_limit;
 
 	struct urb_list urbs;
-	atomic_t lost_pixels; /* 1 = a render op failed. Need screen refresh */
 
 	char mode_buf[1024];
 	uint32_t mode_buf_len;

drivers/gpu/drm/udl/udl_fb.c

···
 		const int byte_offset = line_offset + (clip.x1 << log_bpp);
 		const int dev_byte_offset = (fb->width * i + clip.x1) << log_bpp;
 		const int byte_width = (clip.x2 - clip.x1) << log_bpp;
-		if (udl_render_hline(dev, log_bpp, &urb, (char *)vaddr,
-				     &cmd, byte_offset, dev_byte_offset,
-				     byte_width))
+		ret = udl_render_hline(dev, log_bpp, &urb, (char *)vaddr,
+				       &cmd, byte_offset, dev_byte_offset,
+				       byte_width);
+		if (ret)
 			goto out_drm_gem_shmem_vunmap;
 	}
 

drivers/gpu/drm/udl/udl_main.c

···
 		    urb->status == -ESHUTDOWN)) {
 			DRM_ERROR("%s - nonzero write bulk status received: %d\n",
 				__func__, urb->status);
-			atomic_set(&udl->lost_pixels, 1);
 		}
 	}
 
···
 	/* Wait for an in-flight buffer to complete and get re-queued */
 	ret = down_timeout(&udl->urbs.limit_sem, GET_URB_TIMEOUT);
 	if (ret) {
-		atomic_set(&udl->lost_pixels, 1);
 		DRM_INFO("wait for urb interrupted: %x available: %d\n",
 		       ret, udl->urbs.available);
 		goto error;
···
 	ret = usb_submit_urb(urb, GFP_ATOMIC);
 	if (ret) {
 		udl_urb_completion(urb); /* because no one else will */
-		atomic_set(&udl->lost_pixels, 1);
 		DRM_ERROR("usb_submit_urb error %x\n", ret);
 	}
 	return ret;

drivers/gpu/drm/udl/udl_transfer.c

···
 
 		if (cmd >= cmd_end) {
 			int len = cmd - (u8 *) urb->transfer_buffer;
-			if (udl_submit_urb(dev, urb, len))
-				return 1; /* lost pixels is set */
+			int ret = udl_submit_urb(dev, urb, len);
+			if (ret)
+				return ret;
 			urb = udl_get_urb(dev);
 			if (!urb)
-				return 1; /* lost_pixels is set */
+				return -EAGAIN;
 			*urb_ptr = urb;
 			cmd = urb->transfer_buffer;
 			cmd_end = &cmd[urb->transfer_buffer_length];