topic Re: changing the frame buffer data in i.MX Processors

changing the frame buffer data

bikash — Sat, 19 Sep 2015 09:34:40 GMT

Hi,

I am using a imx6sl base custom board. The data line in LCD we are using are not in order as it should be d0-d23. The data lines are swapped in the lcd panel like d0-d13, d1-d7, d2-d10..... which results colour distortion in image in lcd. We are able to show the actual image in lcd by rearranging the bits of a pixel of the image. I have applied this logic in fb_write function and it works fine if we are writing to frame buffer using write(). But in case of QT application, it is not passing through fb_write and we are getting distorted image in LCD. Can someone tell that which is the ideal place to put my bit rearrange logic so that we can see the image in LCD without colour distortion ?? It's very urgent. Please tell the place just before it is written to LCD.

Re: changing the frame buffer data

igorpadykov — Mon, 21 Sep 2015 07:54:37 GMT

HI bikash

I am afraid i.MX6SL eLCDIF module does not support bit remapping in

hardware, if you are using FSL BSP, for proper place for software remapping

it may be useful to look at attached Linux Manual Chapter 12 ELCDIF Frame Buffer Driver

Best regards

igor

Re: changing the frame buffer data

bikash — Mon, 21 Sep 2015 12:10:17 GMT

Hi,

Can you please share the link of Linux Manual.

Thanks

Bikash

Re: changing the frame buffer data

igorpadykov — Mon, 21 Sep 2015 12:16:55 GMT

https://community.freescale.com/servlet/JiveServlet/download/569524-362092/i.MX_6_Linux_Reference_Manual.pdf

~igor

Re: changing the frame buffer data

bikash — Mon, 21 Sep 2015 14:21:13 GMT

Hi,

I went through the lcdif.c file, it seems like all operation done here is lcd initialization only which happens only at boot time once. Non of the function in this file come to picture at run time like fb_write() in fbmrm.c . I think we have to find a function in frame buffer driver which is executed for each frame and we have to rearrange the bits at that place.

Re: changing the frame buffer data

bikash — Mon, 05 Oct 2015 09:08:09 GMT

Hi, Can someone give some hint on the above problem?

Re: changing the frame buffer data

kennyzhang — Wed, 11 Nov 2015 04:08:21 GMT

Hi all,

I also want to know how to operate the frame buffer like reading or writing after all other apps finished such operation to frame buffer, just before the frame buffer data are shown to display device finally.

Thanks!

Kenny