概述
在调试display时经常使用modetest工具，ｍodetest.c源码由libdrm提供，yocto提供了编译libdrm的方法:
poky/meta/recipes-graphics/drm/libdrm_2.4.91.bb
１、bb文件指定libdrm从网上fetch的路径:
13 SRC_URI = "http://dri.freedesktop.org/libdrm/${BP}.tar.bz2
14 file://installtests.patch
15 file://fix_O_CLOEXEC_undeclared.patch
16 file://0001-configure.ac-Allow-explicit-enabling-of-cunit-tests.patch
17 " ２、bitbake命令编译libdrm；
bitbake libdrm
tmp/work/aarch64-sdrv-linux/libdrm/2.4.91-r0/libdrm-2.4.9目录是check out出来的源码：
libdrm-2.4.91$ ls
aclocal.m4 configure include libsync.h meson.build README xf86atomic.h xf86drmMode.h
amdgpu configure.ac intel m4 meson_options.txt tegra xf86drm.c xf86drmRandom.c
autom4te.cache data libdrm_lists.h Makefile.am nouveau tests xf86drm.h xf86drmRandom.h
build-aux etnaviv libdrm_macros.h Makefile.in omap util_double_list.h xf86drmHash.c xf86drmSL.c
config.h.in exynos libdrm.pc.in Makefile.sources patches util_math.h xf86drmHash.h
config.h.in~ freedreno libkms man tmp/work/aarch64-sdrv-linux/libdrm/2.4.91-r0/image 目录中生成可执行bin文件：
image/
└── usr
├── bin
├── include
├── lib
└── share
ls image/usr/bin/
drmdevice etnaviv_2d_test etnaviv_cmd_stream_test kms-steal-crtc kms-universal-planes modetest random
drmsl etnaviv_bo_cache_test hash kmstest modeprint proptest vbltest
３、modetest使用方法：
modetest可以查询板卡的显示能力，使用-h参数查看详细用法：
modetest -h
usage: modetest [-cDdefMPpsCvw]
Query options:
-c list connectors
-e list encoders
-f list framebuffers
-p list CRTCs and planes (pipes)
Test options:
-P <plane_id>@<crtc_id>:<w>x<h>[+<x>+<y>][*<scale>][@<format>] set a plane
-s <connector_id>[,<connector_id>][@<crtc_id>]:<mode>[-<vrefresh>][@<format>] set a mode
-C test hw cursor
-v test vsynced page flipping
-w <obj_id>:<prop_name>:<value> set property
Generic options:
-d drop master after mode set
-M module use the given driver
-D device use the given device
Default is to dump all info.
modetest 加-M参数再加上DRM driver的名称可以查看显示能力：
比如MTK 的板卡，需要查看connectors、encoders、CRTCs、planes，使用命令：modetest -M mediatek
modetest -M mediatek
Encoders:
id crtc type possible crtcs possible clones
30 44 DSI 0x00000001 0x00000000
32 57 TMDS 0x00000002 0x00000000
38 44 Virtual 0x00000001 0x00000000
51 57 Virtual 0x00000002 0x00000000
Connectors:
id encoder status name size (mm) modes encoders
31 30 connected eDP-1 0x0 1 30
modes:
name refresh (Hz) hdisp hss hse htot vdisp vss vse vtot)
1920x720 60 1920 1944 1960 1984 720 760 768 792 96000 flags: ; type:
props:
1 EDID:
flags: immutable blob
blobs:
value:
2 DPMS:
flags: enum
enums: On=0 Standby=1 Suspend=2 Off=3
value: 0
33 32 connected LVDS-1 293x110 1 32
modes:
name refresh (Hz) hdisp hss hse htot vdisp vss vse vtot)
800x480 30 800 810 822 832 480 490 518 528 13178 flags: ; type: preferred, driver
props:
1 EDID:
flags: immutable blob
blobs:
value:
2 DPMS:
flags: enum
enums: On=0 Standby=1 Suspend=2 Off=3
value: 0
39 38 disconnected (null)-1 0x0 0 38
props:
2 DPMS:
flags: enum
enums: On=0 Standby=1 Suspend=2 Off=3
value: 0
35 WRITEBACK_PIXEL_FORMATS:
flags: immutable blob
blobs:
value:
52473234
52 51 disconnected (null)-2 0x0 0 51
props:
2 DPMS:
flags: enum
enums: On=0 Standby=1 Suspend=2 Off=3
value: 0
35 WRITEBACK_PIXEL_FORMATS:
flags: immutable blob
blobs:
value:
52473234
CRTCs:
id fb pos size
44 70 (0,0) (1920x720)
1920x720 60 1920 1944 1960 1984 720 760 768 792 96000 flags: ; type:
props:
45 PQPARAM:
flags: range
values: 0 18446744073709551615
value: 4294967294
46 PQINDEX:
flags: range
values: 0 18446744073709551615
value: 4294967294
47 COLOR_BYPASS:
flags: range
values: 0 18446744073709551615
value: 4294967294
48 COLOR_WINDOW:
flags: range
values: 0 18446744073709551615
value: 4294967294
49 GET_PQPARAM:
flags: range
values: 0 18446744073709551615
value: 4294967294
23 GAMMA_LUT:
flags: blob
blobs:
value:
24 GAMMA_LUT_SIZE:
flags: immutable range
values: 0 4294967295
value: 512
57 71 (0,0) (800x480)
800x480 30 800 810 822 832 480 490 518 528 13178 flags: ; type: preferred, driver
props:
58 PQPARAM:
flags: range
values: 0 18446744073709551615
value: 4294967294
59 PQINDEX:
flags: range
values: 0 18446744073709551615
value: 4294967294
60 COLOR_BYPASS:
flags: range
values: 0 18446744073709551615
value: 4294967294
61 COLOR_WINDOW:
flags: range
values: 0 18446744073709551615
value: 4294967294
62 GET_PQPARAM:
flags: range
values: 0 18446744073709551615
value: 4294967294
23 GAMMA_LUT:
flags: blob
blobs:
value:
24 GAMMA_LUT_SIZE:
flags: immutable range
values: 0 4294967295
value: 512
Planes:
id crtc fb CRTC x,y x,y gamma size possible crtcs
40 44 70 0,0 0,0 0 0x00000001
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 1
25 alpha:
flags: range
values: 0 255
value: 255
41 0 0 0,0 0,0 0 0x00000001
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 0
25 alpha:
flags: range
values: 0 255
value: 255
42 0 0 0,0 0,0 0 0x00000001
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 0
25 alpha:
flags: range
values: 0 255
value: 255
43 0 0 0,0 0,0 0 0x00000001
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 0
25 alpha:
flags: range
values: 0 255
value: 255
53 57 71 0,0 0,0 0 0x00000002
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 1
25 alpha:
flags: range
values: 0 255
value: 255
54 0 0 0,0 0,0 0 0x00000002
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 0
25 alpha:
flags: range
values: 0 255
value: 255
55 0 0 0,0 0,0 0 0x00000002
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 0
25 alpha:
flags: range
values: 0 255
value: 255
56 0 0 0,0 0,0 0 0x00000002
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 0
25 alpha:
flags: range
values: 0 255
value: 255
Frame buffers:
id size pitch
connectors显示了display连接链路状态：
status=connected说明链路创建ok ,encoders=30说明该connector(id＝31)绑定的encoder id=30;
分辨率：1920x720
刷新率：60帧
Connectors:
id encoder status name size (mm) modes encoders
31 30 connected eDP-1 0x0 1 30
modes:
name refresh (Hz) hdisp hss hse htot vdisp vss vse vtot)
1920x720 60 1920 1944 1960 1984 720 760 768 792 96000 flags: ; type:
hdisp 等参数和source code中设定相同：
560 static const struct drm_display_mode auo_g133han01_mode = {
561 .clock = 96000,
562 .hdisplay = 1920,
563 .hsync_start = 1920 + 32,
564 .hsync_end = 1920 + 32 + 1,
565 .htotal = 1920 + 32 + 1 + 31,
566 .vdisplay = 720,
567 .vsync_start = 720 + 18,
568 .vsync_end = 720 + 18 + 1,
569 .vtotal = 720 + 18 + 1 + 17,
570 .vrefresh = 60,
571 }; 4、planes
plane中的format表面该plane支持的色彩格式：
Planes:
id crtc fb CRTC x,y x,y gamma size possible crtcs
40 44 70 0,0 0,0 0 0x00000001
formats: XR24 XB24 AR24 AB24 RA24 RG24 BG24 RG16 BG16 UYVY YUYV
props:
5 type:
flags: immutable enum
enums: Overlay=0 Primary=1 Cursor=2
value: 1
25 alpha:
flags: range
values: 0 255
value: 255
最后
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