Re: [PATCH v12 1/3] drm: rockchip: Add basic drm driver

Hi Daniel,

On Tue, 18 Nov 2014 09:32:34 +0100
Daniel Vetter [off-list ref] wrote:

On Tue, Nov 18, 2014 at 04:00:29PM +0800, Mark Yao wrote:

quoted

From: Mark yao <redacted>

This patch adds the basic structure of a DRM Driver for Rockchip Socs.

Signed-off-by: Mark Yao <redacted>
Signed-off-by: Daniel Kurtz <redacted>
Acked-by: Daniel Vetter <redacted>
Reviewed-by: Rob Clark <redacted>
---
Changes in v2:
- use the component framework to defer main drm driver probe
  until all VOP devices have been probed.
- use dma-mapping API with ARM_DMA_USE_IOMMU, create dma mapping by
  master device and each vop device can shared the drm dma mapping.
- use drm_crtc_init_with_planes and drm_universal_plane_init.
- remove unnecessary middle layers.
- add cursor set, move funcs to rockchip drm crtc.
- use vop reset at first init
- reference framebuffer when used and unreference when swap out vop

Changes in v3:
- change "crtc->fb" to "crtc->primary-fb"
Adviced by Daniel Vetter
- init cursor plane with universal api, remove unnecessary cursor set,move 

Changes in v4:
Adviced by David Herrmann
- remove drm_platform_*() usage, use register drm device directly.

Minor fixup for that part below.

[snip]

quoted

+static int rockchip_drm_bind(struct device *dev)
+{
+	struct drm_device *drm;
+	int ret;
+
+	drm = drm_dev_alloc(&rockchip_drm_driver, dev);
+	if (!drm)
+		return -ENOMEM;
+
+	ret = drm_dev_set_unique(drm, "%s", dev_name(dev));
+	if (ret)
+		goto err_free;

Please call rockchip_drm_load here directly and don't put it as the ->load
function into the driver vtable. The point of the alloc/register split is
that the driver can be completely set up _before_ we register anything.
But for backwards compat and historical reasons ->load is called somewhere
in the middle (so that you could access the minor nodes if needed, since
some drivers do that).

I tried to do the same in the atmel-hlcdc DRM driver, but I need the
primary drm_minor to register the connectors (see this kernel
backtrace [1]), which means I either initialize the connector in the
wrong place (currently part of the drm load process), or I just can't
call atmel_hlcdc_dc_load before registering the drm device...

Regards,

Boris

[1]http://code.bulix.org/fi7trt-87436


-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com