From 26594678d00f94c62f2e43162bd6d10fd0b74917 Mon Sep 17 00:00:00 2001 From: Leandro Ribeiro Date: Wed, 9 Jun 2021 20:00:38 -0300 Subject: [PATCH] drm/doc: document how userspace should find out CRTC index In this patch we add a section to document what userspace should do to find out the CRTC index. This is important as they may be many 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 Reviewed-by: Pekka Paalanen Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210609230039.73307-2-leandro.ribeiro@collabora.com --- Documentation/gpu/drm-uapi.rst | 13 +++++++++++++ drivers/gpu/drm/drm_debugfs_crc.c | 8 ++++---- include/uapi/drm/drm.h | 4 ++-- 3 files changed, 19 insertions(+), 6 deletions(-) diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst index 04bdc7a..7e51dd4 100644 --- a/Documentation/gpu/drm-uapi.rst +++ b/Documentation/gpu/drm-uapi.rst @@ -457,6 +457,19 @@ Userspace API Structures .. kernel-doc:: include/uapi/drm/drm_mode.h :doc: overview +.. _crtc_index: + +CRTC index +---------- + +CRTC's have both an object ID and an index, and they are not the same thing. +The index is used in cases where a densely packed identifier for a CRTC is +needed, for instance a bitmask of CRTC's. The member possible_crtcs of struct +drm_mode_get_plane is an 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. + .. kernel-doc:: include/uapi/drm/drm.h :internal: diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c index 3dd70d8..bbc3bc4 100644 --- a/drivers/gpu/drm/drm_debugfs_crc.c +++ b/drivers/gpu/drm/drm_debugfs_crc.c @@ -46,10 +46,10 @@ * it reached a given hardware component (a CRC sampling "source"). * * Userspace can control generation of CRCs in a given CRTC by writing to the - * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC. - * Accepted values are source names (which are driver-specific) and the "auto" - * keyword, which will let the driver select a default source of frame CRCs - * for this CRTC. + * file dri/0/crtc-N/crc/control in debugfs, with N being the :ref:`index of + * the CRTC`. Accepted values are source names (which are + * driver-specific) and the "auto" keyword, which will let the driver select a + * default source of frame CRCs for this CRTC. * * Once frame CRC generation is enabled, userspace can capture them by reading * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index d043752..e1f49dd 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -635,8 +635,8 @@ struct drm_gem_open { /** * DRM_CAP_VBLANK_HIGH_CRTC * - * If set to 1, the kernel supports specifying a CRTC index in the high bits of - * &drm_wait_vblank_request.type. + * If set to 1, the kernel supports specifying a :ref:`CRTC index` + * in the high bits of &drm_wait_vblank_request.type. * * Starting kernel version 2.6.39, this capability is always set to 1. */ -- 2.7.4