Re: [PATCH v4 1/6] drm: add SimpleDRM driver

Hi Tom

On Sat, Sep 21, 2013 at 4:18 PM, Tom Gundersen teg@jklm.no wrote:

Hi David,

On Sun, Sep 1, 2013 at 3:36 PM, David Herrmann dh.herrmann@gmail.com wrote:

...

The SimpleDRM driver binds to simple-framebuffer devices and provides a DRM/KMS API. It provides only a single CRTC+encoder+connector combination plus one initial mode.

Userspace can create one dumb-buffer and attach it to the CRTC. Only if the buffer is destroyed, a new buffer can be created. The buffer is directly mapped into user-space, so we have only resources for a single buffer. Otherwise, shadow buffers plus damage-request would be needed.

Signed-off-by: David Herrmann dh.herrmann@gmail.com Tested-by: Stephen Warren swarren@nvidia.com

---

[...]

...

+static int sdrm_conn_fill_modes(struct drm_connector *conn, uint32_t max_x,

•                           uint32_t max_y)
  

+{

•   struct sdrm_device *sdrm = conn->dev->dev_private;
  

•   struct drm_display_mode *mode;
  

•   int ret;
  

•   if (conn->force == DRM_FORCE_ON)
  

•           conn->status = connector_status_connected;
  

•   else if (conn->force)
  

•           conn->status = connector_status_disconnected;
  

•   else
  

•           conn->status = connector_status_connected;
  

•   list_for_each_entry(mode, &conn->modes, head)
  

•           mode->status = MODE_UNVERIFIED;
  

•   mode = drm_gtf_mode(sdrm->ddev, sdrm->fb_width, sdrm->fb_height,
  

•                       60, 0, 0);
  

•   if (mode) {
  

•           mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
  

•           drm_mode_probed_add(conn, mode);
  

•           sdrm->mode = mode;
  

Should you also be setting sdrm->fb_{width,height} to mode->{v,h}display here? Otherwise, due to the rounding in drm_gtf_mode(), these values won't necessarily match (which I suppose they must?).

What the ****. I wasn't aware drm_gtf_mode() modifies the v/hdisplay values. Hm.. I will probably have to use something else then.

Thanks David