could not find HDMI 1280x800 mode on iMX8MP

[Miles_x]

Hi NXP support,

we have to display on HDMI , using mode 1280x800,  platform is iMX8MP, bsp version 5.10.52-2.1.0.

but we could not find HDMI 1280x800 mode on board, juse see list below:

root@imx8mp-evk :/sys/class/drm/card1-HDMI-A-1# cat modes
1920x1080
1920x1080
1920x1080
1920x1080
1600x900
1280x1024
1280x1024
1152x864
1280x720
1280x720
1280x720
800x600
800x600
720x576
720x576
720x480
720x480
720x480
720x480
640x480
640x480
640x480

and we find source code drm_edid.c has the mode definition:

    /* 0x1c - 1280x800@60Hz */

    { DRM_MODE("1280x800", DRM_MODE_TYPE_DRIVER, 83500, 1280, 1352,

           1480, 1680, 0, 800, 803, 809, 831, 0,

           DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC) },

and source code  phy-fsl-samsung-hdmi.c has the clock:

    }, {

        83500000, {

            0x00, 0xD1, 0x68, 0x58, 0x8D, 0x06, 0x00, 0x40,

            0x4F, 0x30, 0x33, 0x65, 0x10, 0x94, 0x24, 0x80,

            0x6C, 0xF2, 0x67, 0x00, 0x10, 0x85, 0x30, 0x3A,

            0x74, 0x8F, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00,

            0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

            0x00, 0xE0, 0x83, 0x0F, 0x3E, 0xF8, 0x00, 0x00,

        },

please tell us, why the mode 1280x800 is not avialable?

[Miles_x]

Hi joanxie,

pixel clock we used is 1680x831x60 = 83764800,  about 83.7M

[joanxie]

pls tell me what pixel clock of your hdmi display is

[Miles_x]

Hi joanxie,

pixel clock we used is 1680x831x60 = 83764800,  about 83.7M

[joanxie]

this week, I couldn't go back to office to offer this, you can refer to this link firstly, if failed, pls tell me

https://community.nxp.com/t5/i-MX-Processors/IMX8M-plus-1280-800-resolution/m-p/1732918

[Miles_x]

we have read the topic (https://community.nxp.com/t5/i-MX-Processors/IMX8M-plus-1280-800-resolution/m-p/1732918) before, and add the entry of 83500000 in  samsung_phy_pll_cfg。 but we still not  see the mode "1280x800"  on board,  when using command "cat "/sys/class/drm/card1-HDMI-A-1/modes" .  

so what is the critical point for the problem?

[joanxie]

give me your logfile, let me double check it

[luo44atosu]

what's the samsung_phy_pll_cfg setting for 77MHZ pixel clock? Also could you please post the correct register setting in the imx8mp user manual? Is the imx8mp and imx8mm the same on HDMI?