请教关于8168无法输出boot logo到VGA的问题

8168+DVRRDK
使用IOUTA~IOUTC，连接到视频放大器，再引出RGB信号，行、场信号用的AR8和AL9。
uboot启动时，没有输出logo。测量IOUTA~IOUTC，都没有波形，一直是0V。行、场信号也没有波形
参考
http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/p/247546/867752#867752
操作如下
mw.b 0x81000000 0xFF 0x300000
tftp 0x81000000 samplelogo_640x480.bmp
nand erase 0x00280000 0x300000
nand write 0x81000000 0x00280000 0x300000
setenv bootcmd ' logo on 0x280000 0x81000000 0xA0000000 40 60'
重启之后，uboot无法进入命令行
看到有人说修改device.c中的
omap_mux_init_signal("tsi5_bytstrt", OMAP_MUX_MODE2);
omap_mux_init_signal("tsi5_pacval", OMAP_MUX_MODE2);
可是这个c文件是在kernel中的，并不在uboot中，应该不是这个问题。
问题一：RDK是否支持从模拟DAC接口输出boot logo
问题二：如何确认uboot是否对DAC进行了配置
在cmd_logo_816x.c中看到了如下语句
       /*enable the DAC_CORE*/
       WR_MEM_32(0x48140660, 0x1);
       /*set the HSYNC/VSYNC for HDCOMP, use DVO1 signal, this
       is for PG2.0 or above silicon only*/      
       if ( get_cpu_rev() >= PG2_0) [
              /*these settings matches DVR reference,
              it may not work with DM816X EVM*/
              WR_MEM_32(0x4814086c, 0x2);
              WR_MEM_32(0x48140870, 0x2);
              WR_MEM_32(0x48140724, 0x2);
可是用md命令读0x4814086c和0x48140870，返回全是0。
https://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/t/240982
里边提到可以查看寄存器设置，请问查询命令是什么。试过mdump，提示非法命令。
问题三：管脚复用问题
手册P262中
   For example, these are the steps required to use the pins AR8 and AL9 as the DAC_HSYNC and VSYNC signals:
1. Set the PINCTRLx registers for AR8 and AL9 as follows:
• 0x4814 0894 = 0x00000001
• 0x4814 0898 = 0x00000001
2. Select analog VENC sync out option as follows:
• 0x4814 0724 = 0x00000004
cmd_logo_816x.c中的
REG32(CSL_TI816x_CTRL_MODULE_BASE + 0x0894) = 1;   //37  tsi7_bytstrt  vout0_fld
REG32(CSL_TI816x_CTRL_MODULE_BASE + 0x0898) = 1;   //38  tsi7_pacval   vout0_avid
       /*enable the DAC_CORE*/
       WR_MEM_32(0x48140660, 0x1);
       /*set the HSYNC/VSYNC for HDCOMP, use DVO1 signal, this
       is for PG2.0 or above silicon only*/   
       if ( get_cpu_rev() >= PG2_0) [
              /*these settings matches DVR reference,
              it may not work with DM816X EVM*/
              WR_MEM_32(0x4814086c, 0x2);
              WR_MEM_32(0x48140870, 0x2);
              WR_MEM_32(0x48140724, 0x2);
是否需要将WR_MEM_32(0x48140724, 0x2);改为WR_MEM_32(0x48140724, 0x4);
问题四：uboot启动时，会在串口输出如下字符图形，该图形是否可以修改？
:,;;:;:;;;;;;;;r;;:,;;:;:;;;;;;;;:,;;:;:;;;;;;;;:,;;:;:;;;;;;;;:;;;;;;;;:,;;:;:
;,;:::;;;;r;;;rssiSiS552X5252525259GX2X9hX9X9XX2325S55252i5:,;;:;:;;;;;;;;:,;;:
;:;;;;;;;rrssSsS52S22h52299GGAAMHMM#BBH#B#HMM#HMBA&&XX2255S2S5Si:,;;:;:;;;;;;;;
;:;;r;;rsrrriiXS5S329&A&MH#BMB#A&9XXA252GXiSXX39AAMMMBB&G22S5i2SSiiiisi:,;;:;:;
;;;;;r;rr2iisiih393HB#B#AA99i22irrrX3X52AGsisss2Xii2299HBMA&X2S5S5iSiisSsi:,;;:
r:r;rrsrsihXSi2&##MHB&Ahh3AGHGA9G9h&#H##@@@##MAMMXXX9SSS29&&HGGX2i5iisiiisisi:,
;;rrrrsSiiiA&ABH&A9GAGhAhBAMHA9HM@@@@@@@@@@@@@@@@@@@HHhAh2S2SX9&Gh22SSiisiiisii
r:rrssisiS2XM##&h3AGAX&3GG3Ssr5H@M#HM2; ;2X&&&MHMB###GBB#B&XXSSs529XX55iSsisisi
r;rsrisSi2XHAhX99A3XXG&&XS;:,rH#HGhAS   @@@@3rs2XBM@@A552&&AHA2XiisSS252SSsisSs
r;issi5S22&&3iSSX292&hXsr;;:;h@&G339&S9@@@@2@MA&9&HB##Xris29ABMAAX2ir;rsSi5iss5
rrsSi2XhG&9GXh399&X99i;;;;;;r#H&293H9X#@@@@@@@B&9GhAH@XrrsrsiXABHB&HG2rr;rrSiSi
;:rsisS599&AA9XG&3A35r;:::;,;BMh&&2iX5A@@@@@@@&392X5GB2;;;r;iSX393A##A&Xi:::rsi
;:rss552222X553&XHMhir;;::,:,h#HhGSXhG3#@@@@#AXXS2XAHA;::;;;;ss55XShBA3239r:,;;
r;ii2S5SSi2i53hirsh2srr::,,,,;MMXX359&Ah3h&Si59SX99A#i:,::::;;sri2,.2r;:SGAr;,:
;:;rrrrssiriXGSi::shs;;;,,,:,,rBBA9h5s5h5iS5isi2SAHB5:,,,:::;rrs5&SrisSX5Srrr:,
;,r;;;;rsriSSrrrr;;5Xrr;;,:,,.,;9AA2SsisS5323XXXG9&i:.,,::;;r;;;srrrrrr;;:;::::
:,;r;r;rrissrrr;:;::;s;;;;,:,,..,r293h222hXXAAGGGX;:,,,:,:,::;:;::,:,,,,...,,,,
;,;;;;rrrrrrrrirr;,.,,:::::::,,,,.,;SX&ABAB2hhXir:,,.,,.,,:,,,,..,,,..,..,,,..:
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