Hi, Igor,
Thank you for reply.
I'm sorry less information.
Device is i.MX 6DQ and reference manual is IMX6DQRM rev4, below register.

I use IPU1 and address is 0x265_80E8 with Parallel Display CLAA-WVGA with SABRESD.
I use a command [setenv mmcargs 'setenv bootargs console=${console},${baudrate} ${smp} root=${mmcroot} video=mxcfb0:dev=lcd,CLAA-WVGA,if=RGB565'] at uboot , then boot up Linux.
Then the resister value is 0x320=800pixel, but I changed it, nothing happen.
What is configured by this register?
Best Regards,
Sugiyama