On 1/30/19 4:02 PM, Daniel Vetter wrote: > 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 > Sounds good. Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx> Nicholas Kazlauskas _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
