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Custom LCD mode not found by Linux

Question asked by Erez Steinberg on May 13, 2015
Latest reply on May 13, 2015 by igorpadykov

Hi experts,

 

I have a custom LCD that I connect to an iMX6DL, running Linux 3.10.53.

 

I made the following adjustments:

(1) Device-tree -- Updated relevant interface parameters. Changed mode_str for mxc_sdc_fb node to hold the new LCD string.

(2) In mxc_lcdif.c  -- added new entry to lcdif_modedb[]

 

It seems the driver attempts to find the LCD mode in the modedb[], but the function 'mxcfb_check_var()' always returns 0.

 

I enabled DEBUG for device-driver printouts -

 

mxc_lcdif lcd.26: mxc_lcdif_probe enter

mxc_lcdif lcd.26: mxc_lcdif_probe exit

mxc_sdc_fb fb.25: mxcfb_probe enter

(NULL device *): Mode Str = CUSTOM_LCD

modedb fb_find_mode: mode option = CUSTOM_LCD

modedb fb_find_mode: Trying specified video mode (ignoring refresh rate) 0x0

modedb fb_find_mode: Trying best-fit modes

modedb fb_find_mode: Trying 800x480

modedb fb_try_mode: Trying mode CLAA-WVGA 800x480-4@57

modedb fb_try_mode:  calling fb_check_var()

modedb fb_try_mode:  Mode CLAA-WVGA -- err = 0

modedb fb_find_mode: Trying 800x480

modedb fb_try_mode: Trying mode SEIKO-WVGA 800x480-4@60

modedb fb_try_mode:  calling fb_check_var()

modedb fb_try_mode:  Mode SEIKO-WVGA -- err = 0

modedb fb_find_mode: Trying 320x240

modedb fb_try_mode: Trying mode CUSTOM_LCD 320x240-4@60

modedb fb_try_mode:  calling fb_check_var()

modedb fb_try_mode:  Mode CUSTOM_LCD -- err = 0

modedb fb_find_mode: Trying default video mode

modedb fb_try_mode: Trying mode CLAA-WVGA 800x480-24@57

modedb fb_try_mode:  calling fb_check_var()

modedb fb_try_mode:  Mode CLAA-WVGA -- err = 0

 

 

Any suggestions?

 

By the way-- if the LCD is defined in the DTB, do I also need to have video=...  in bootargs?

 

Sincerely,

Erez

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