4k 是假的吗？

connet · 发表于 2014-11-19 13:00:12

测试发现，即使android 选择4k 输出， android 系统运行状态还是1080p，所谓的4k是不是把 1080p 的framebuffer scale输出到 4k 显示器(新下载的11月版本)？
请问如何修改 kernel 分辨率，让 android 运行在 4k分辨率下？

isle · 发表于 2014-11-19 16:39:55

一般FB 是FHD， HDMI 会scale到4k。播放ideo的是时候video输出video buffer直接 4K。无 scale 。
FB直接4K 没试过。内存会紧张吧。楼主有啥需求要FB 4K？

openeyes · 发表于 2014-11-19 17:01:27

那一張4k2k的bmp檔,顯示出來不就失真了?

isle · 发表于 2014-11-19 17:26:38

好吧，FB改4K的地方在kernel/arch/arm/boot/dts/lcd-box.dtsi
disp_timings: display-timings {
native-mode = <&timing1>;

改成 native-mode = <&timing2>;

暴走的阿Sai · 发表于 2014-11-19 17:51:03

4K是一个分辨率标准，4K还包括解码能力，可以播放4K高清的视频，至于Android和HDMI的buffer也可以改大

connet · 发表于 2014-11-20 10:03:50

把 kernel/arch/arm/boot/dts/lcd-box.dtsi 修改为改成 native-mode = <&timing2>; 编译出 resource.img，更新后不是4k，变成1280x720，4k 失败自动回到720p ?

isle · 发表于 2014-11-20 14:25:51

把 cat /sys/class/graphics/fb0/disp_info 信息贴上来。

sky · 发表于 2014-11-20 19:45:16

电视是4K吗?

connet · 发表于 2014-11-21 10:32:07

烧写4k resource.img 后显示 /sys/class/graphics/fb0/disp_info

z-order:
layer3_sel_win[3]
layer2_sel_win[2]
layer1_sel_win[1]
layer0_sel_win[0]
win0:
state:0, fmt:ARGB888, y_vir:320, uv_vir:320
xact: 320, yact: 240, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0
y_h_fac: 4096, y_v_fac: 4096, uv_h_fac: 4096, uv_v_fac: 4096
y_addr: 0x00000000, uv_addr:0x00000000
win1:
state:1, fmt:ARGB888, y_vir:3840, uv_vir:0
xact:1280, yact: 720, dsp_x:3840, dsp_y:2160, x_st: 0, y_st: 0
y_h_fac: 21825, y_v_fac: 21809, uv_h_fac: 4096, uv_v_fac: 4096
y_addr: 0x10000000, uv_addr:0x00000000
win2:
state:0
fmt:ARGB888
area0: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area1: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area2: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area3: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
win3:
state:0
fmt:ARGB888
area0: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area1: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0 addr:0x00000000
area2: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area3: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000

复制代码

马上 reboot 后变成

z-order:
layer3_sel_win[3]
layer2_sel_win[2]
layer1_sel_win[1]
layer0_sel_win[0]
win0:
state:0, fmt:ARGB888, y_vir:320, uv_vir:320
xact: 320, yact: 240, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0
y_h_fac: 4096, y_v_fac: 4096, uv_h_fac: 4096, uv_v_fac: 4096
y_addr: 0x00000000, uv_addr:0x00000000
win1:
state:1, fmt:ARGB888, y_vir:3840, uv_vir:0
xact:1920, yact:1080, dsp_x:3840, dsp_y:2160, x_st: 0, y_st: 0
y_h_fac: 32750, y_v_fac: 32737, uv_h_fac: 4096, uv_v_fac: 4096
y_addr: 0x13f48000, uv_addr:0x00000000
win2:
state:0
fmt:ARGB888
area0: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area1: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area2: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area3: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
win3:
state:0
fmt:ARGB888
area0: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area1: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0 addr:0x00000000
area2: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000
area3: state:0, y_vir: 320, dsp_x: 320, dsp_y: 240, x_st: 0, y_st: 0, addr:0x00000000

复制代码

重启过程可以看到屏幕中央的 android 图标明显变小很多，似乎4k 有效了，但是进入android 后，第一次是720p 分辨率，之后重启都是1080p，貌似android 系统拒绝了4k模式？

isle · 发表于 2014-11-21 10:50:48

依照你的描述应该是kernel已经生效了。android做了限制。
我在ubuntu上试过了。FB 4K是没问题。
这个需要android上层修改。可能比较麻烦点。
我先找找有没有解决方案吧。