topic Re: About imx8mm mipi write interface in i.MX Processors

About imx8mm mipi write interface

13660284951 — Fri, 24 Apr 2020 05:53:18 GMT

hello:nxp friends?

I had some questions with imx8mm on android9 platform?

No1： use 《 mipi_dsi_dcs_write_buffer() 》 this interface write lcd parasm,while i found,it can not long write?

No2：while use uuu to download firmware to emmc on ubuntu18,the adb and fastboot is ok,while it return error with log is "FB:ucmd setenv fastboot_dev mmc"

Re: About imx8mm mipi write interface

13660284951 — Fri, 24 Apr 2020 06:02:14 GMT

By the way

No1：The imx8mm manual told us imx8mm is no longer supported framebuffer device,use drm instead?

so the log

[ 1.300514] Unable to create device for framebuffer 0; errno = -19

is ring way?

And sysfs in /dev or /class/sys/graphics are not created fbx device node

Re: About imx8mm mipi write interface

igorpadykov — Fri, 24 Apr 2020 09:56:32 GMT

Hi zhou

seems rm67191 driver have dcs long write for backlight brightness setting

function mipi_dsi_dcs_set_display_brightness() :

panel-raydium-rm67191.c\panel\drm\gpu\drivers - linux-imx - i.MX Linux kernel

>The imx8mm manual told us imx8mm is no longer supported framebuffer device,use drm instead?

please check Linux 5.4.3_1.0.0 Documentation for supported functionality.

Best regards
igor
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Re: About imx8mm mipi write interface

13660284951 — Mon, 27 Apr 2020 06:10:42 GMT

thanks igorpadykov

I had a question,when i call mipi_dsi_dcs_write_buffer() interface to write cmd data,it return 0 to us not erro code?

what happen?

while call mipi_dsi_dcs_read() interface to read lcd id,that return 1 correct to us?

what happen? @igorpadykov

i was confused

Re: About imx8mm mipi write interface

13660284951 — Mon, 27 Apr 2020 06:11:50 GMT

thanks igorpadykov

I had a question,when i call mipi_dsi_dcs_write_buffer() interface to write cmd data,it return 0 to us not erro code?

what happen?

while call mipi_dsi_dcs_read() interface to read lcd id,that return 1 byte correct value to us?

what happen? @igorpadykov

i was confused