On Wed, Jan 30, 2019 at 05:33:00PM +0000, Kazlauskas, Nicholas wrote: > On 1/30/19 11:30 AM, Daniel Vetter wrote: > > It only talks about crtc, brings up intel as an exampel and I think is > > nit: Should be "example". Will fix when applying. > > more misleading than useful really. Plus we have lots of discussion > > about how your standard kms driver should be initialized/cleaned up, > > so maybe better to document this when we have a better idea. > > > > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx> > > --- > > Documentation/gpu/drm-kms.rst | 96 ----------------------------------- > > 1 file changed, 96 deletions(-) > > > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > > index 75c882e09fee..23a3c986ef6d 100644 > > --- a/Documentation/gpu/drm-kms.rst > > +++ b/Documentation/gpu/drm-kms.rst > > @@ -410,102 +410,6 @@ Encoder Functions Reference > > .. kernel-doc:: drivers/gpu/drm/drm_encoder.c > > :export: > > > > -KMS Initialization and Cleanup > > -============================== > > - > > -A KMS device is abstracted and exposed as a set of planes, CRTCs, > > -encoders and connectors. KMS drivers must thus create and initialize all > > -those objects at load time after initializing mode setting. > > - > > -CRTCs (:c:type:`struct drm_crtc <drm_crtc>`) > > --------------------------------------------- > > - > > -A CRTC is an abstraction representing a part of the chip that contains a > > -pointer to a scanout buffer. Therefore, the number of CRTCs available > > -determines how many independent scanout buffers can be active at any > > -given time. The CRTC structure contains several fields to support this: > > -a pointer to some video memory (abstracted as a frame buffer object), a > > -display mode, and an (x, y) offset into the video memory to support > > -panning or configurations where one piece of video memory spans multiple > > -CRTCs. > > This is mostly a duplicate of what's already in the CRTC abstraction > section but it may be worth carrying over the bit about "the number of > CRTCs available determining the number of independent scanout buffers > that can be active at any given time". Oh I didn't even read this. This is just plain wrong and probably predates drm_plane (when it kinda was true-ish, if you'd ignore cursors). Now this would map to number of drm_planes, except - cursors can still be an exceptions - yuv multi-planar might or might not be multiple planes per drm_plane. Aka it's really complicated :-) This is definitely much better explained in the kms overview section at the top of: https://dri.freedesktop.org/docs/drm/gpu/drm-kms.html#overview Plus everything that's getting linked from there ofc. > > - > > -CRTC Initialization > > -~~~~~~~~~~~~~~~~~~~ > > - > > -A KMS device must create and register at least one struct > > -:c:type:`struct drm_crtc <drm_crtc>` instance. The instance is > > -allocated and zeroed by the driver, possibly as part of a larger > > -structure, and registered with a call to :c:func:`drm_crtc_init()` > > -with a pointer to CRTC functions. > > - > > - > > -Cleanup > > -------- > > - > > -The DRM core manages its objects' lifetime. When an object is not needed > > -anymore the core calls its destroy function, which must clean up and > > -free every resource allocated for the object. Every > > -:c:func:`drm_\*_init()` call must be matched with a corresponding > > -:c:func:`drm_\*_cleanup()` call to cleanup CRTCs > > -(:c:func:`drm_crtc_cleanup()`), planes > > -(:c:func:`drm_plane_cleanup()`), encoders > > -(:c:func:`drm_encoder_cleanup()`) and connectors > > -(:c:func:`drm_connector_cleanup()`). Furthermore, connectors that > > -have been added to sysfs must be removed by a call to > > -:c:func:`drm_connector_unregister()` before calling > > -:c:func:`drm_connector_cleanup()`. > > - > > -Connectors state change detection must be cleanup up with a call to > > -:c:func:`drm_kms_helper_poll_fini()`. > > - > > -Output discovery and initialization example > > -------------------------------------------- > > - > > -.. code-block:: c > > - > > - void intel_crt_init(struct drm_device *dev) > > - { > > - struct drm_connector *connector; > > - struct intel_output *intel_output; > > - > > - intel_output = kzalloc(sizeof(struct intel_output), GFP_KERNEL); > > - if (!intel_output) > > - return; > > - > > - connector = &intel_output->base; > > - drm_connector_init(dev, &intel_output->base, > > - &intel_crt_connector_funcs, DRM_MODE_CONNECTOR_VGA); > > - > > - drm_encoder_init(dev, &intel_output->enc, &intel_crt_enc_funcs, > > - DRM_MODE_ENCODER_DAC); > > - > > - drm_connector_attach_encoder(&intel_output->base, > > - &intel_output->enc); > > - > > - /* Set up the DDC bus. */ > > - intel_output->ddc_bus = intel_i2c_create(dev, GPIOA, "CRTDDC_A"); > > - if (!intel_output->ddc_bus) { > > - dev_printk(KERN_ERR, &dev->pdev->dev, "DDC bus registration " > > - "failed.\n"); > > - return; > > - } > > - > > - intel_output->type = INTEL_OUTPUT_ANALOG; > > - connector->interlace_allowed = 0; > > - connector->doublescan_allowed = 0; > > - > > - drm_encoder_helper_add(&intel_output->enc, &intel_crt_helper_funcs); > > - drm_connector_helper_add(connector, &intel_crt_connector_helper_funcs); > > - > > - drm_connector_register(connector); > > - } > > - > > -In the example above (taken from the i915 driver), a CRTC, connector and > > -encoder combination is created. A device-specific i2c bus is also > > -created for fetching EDID data and performing monitor detection. Once > > -the process is complete, the new connector is registered with sysfs to > > -make its properties available to applications. > > - > > KMS Locking > > =========== > > > > > > Everything else looks fine to drop. > > The bits about initialization/cleanup/subclassing/connectors can all be > found in the Atomic Mode Setting section or one of the abstraction sections. With the one thing you wanted to keep also wrong - ok with this patch? Thanks for taking a look at this. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
