On 5/12/21 10:04 AM, Pekka Paalanen wrote: > On Wed, 12 May 2021 09:50:14 -0300 > Leandro Ribeiro <leandro.ribeiro@xxxxxxxxxxxxx> wrote: > >> On 5/6/21 5:50 AM, Pekka Paalanen wrote: >>> On Wed, 28 Apr 2021 18:36:50 -0300 >>> Leandro Ribeiro <leandro.ribeiro@xxxxxxxxxxxxx> wrote: >>> >>>> In this patch we add a section to document what userspace should do to >>>> find out the CRTC index. This is important as there are multiple places >>>> in the documentation that need this, so it's better to just point to >>>> this section and avoid repetition. >>>> >>>> Signed-off-by: Leandro Ribeiro <leandro.ribeiro@xxxxxxxxxxxxx> >>>> --- >>>> Documentation/gpu/drm-uapi.rst | 14 ++++++++++++++ >>>> drivers/gpu/drm/drm_debugfs_crc.c | 9 +++++---- >>>> include/uapi/drm/drm.h | 3 ++- >>>> 3 files changed, 21 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst >>>> index 04bdc7a91d53..1aa52a6ac567 100644 >>>> --- a/Documentation/gpu/drm-uapi.rst >>>> +++ b/Documentation/gpu/drm-uapi.rst >>>> @@ -457,6 +457,20 @@ Userspace API Structures >>>> .. kernel-doc:: include/uapi/drm/drm_mode.h >>>> :doc: overview >>>> >>>> +.. _crtc_index: >>>> + >>>> +CRTC index >>>> +---------- >>>> + >>>> +In some situations, it is important for userspace to find out the index of a >>> >>> That could be said about everything, so this sentence has no >>> information value. Instead, you could start by stating that CRTCs have >>> both an object ID and an index, and they are not the same thing. CRTC >>> index is used in cases where a densely packed identifier for a CRTC is >>> needed, e.g. in bit-for-crtc masks, where using the object ID would not >>> work. >>> >>>> +CRTC. The CRTC index should not be confused with its object id. >>>> + >>>> +In order to do this, userspace should first query the resources object >>> >>> Instead of saying what userspace must do, you could just explain where >>> it can be observed. >>> >>>> +from the device that owns the CRTC (using the DRM_IOCTL_MODE_GETRESOURCES >>> >>> So here you might start with: DRM_IOCTL_MODE_GETRESOURCES populates a >>> structure with an array of CRTC IDs. CRTC's index is its index in that >>> array. >>> >>>> +ioctl). The resources object contains a pointer to an array of CRTC's, and also >>>> +the number of entries of the array. The index of the CRTC is the same as its >>>> +position in this array. >>> >>> Anyway, the idea here is right. >>> >> >> So what about: >> >> CRTC's have both an object ID and an index, and they should not be >> confused. The index is used in cases where a densely packed identifier >> for a CRTC is needed, for instance in a bitmask of CRTC's. (maybe a link >> to the possible_crtcs field of struct drm_mode_get_plane? as example) >> >> DRM_IOCTL_MODE_GETRESOURCES populates a structure with an array of CRTC >> id's, and the CRTC index is its position in this array. > > Sure, sounds good. > > Capitalized 'ID'? > Sure, I'll add this change. Thanks, Leandro
