Re: [PATCH v7 3/3] drm: Add GUD USB Display driver

Den 05.03.2021 17.31, skrev Noralf Trønnes:

This adds a USB display driver with the intention that it can be used with future USB interfaced low end displays/adapters. The Linux gadget device driver will serve as the canonical device implementation.

diff --git a/drivers/gpu/drm/gud/gud_drv.c b/drivers/gpu/drm/gud/gud_drv.c

+static int gud_probe(struct usb_interface *intf, const struct usb_device_id *id) +{

• num_formats_dev = ret;
• for (i = 0; i < num_formats_dev; i++) {

• const struct drm_format_info *info;
  

• size_t fmt_buf_size;
  

• u32 format;
  

• format = gud_to_fourcc(formats_dev[i]);
  

• if (!format) {
  

• 	drm_dbg(drm, "Unsupported format: 0x%02x\n", formats_dev[i]);
  

• 	continue;
  

• }
  

• if (format == GUD_DRM_FORMAT_R1)
  

• 	info = &gud_drm_format_r1;
  

• else if (format == GUD_DRM_FORMAT_RGB111)
  

• 	info = &gud_drm_format_rgb111;
  

• else
  

• 	info = drm_format_info(format);
  

• switch (format) {
  

• case GUD_DRM_FORMAT_R1:
  

• 	fallthrough;
  

• case GUD_DRM_FORMAT_RGB111:
  

• 	xrgb8888_emulation_format = info;
  

• 	break;
  

• case DRM_FORMAT_RGB565:
  

• 	rgb565_supported = true;
  

• 	if (!xrgb8888_emulation_format)
  

• 		xrgb8888_emulation_format = info;
  

• 	break;
  

• case DRM_FORMAT_XRGB8888:
  

• 	xrgb8888_supported = true;
  

• 	break;
  

• };
  

• fmt_buf_size = drm_format_info_min_pitch(info, 0, drm->mode_config.max_width) *
  

• 	       drm->mode_config.max_height;
  

• max_buffer_size = max(max_buffer_size, fmt_buf_size);
  

• if (format == GUD_DRM_FORMAT_R1)
  

This line should be:

if (format == GUD_DRM_FORMAT_R1 || format == GUD_DRM_FORMAT_RGB111)

There's also a bug in the format conversion functions that shows up on transfers with widths that are not pixels per byte aligned. I've fixed R1, I'll look at RGB111 tomorrow.

Noralf.

• 	continue; /* Internal not for userspace */
  

• formats[num_formats++] = format;
  

• }