Hello,

I am using AT91SAM9261EK board with board package on at91.com.

I have encountered a problem with displaying image on the LCD.

Upon system startup, if the application to display the image is executed immediately after login, the image display will be as shown in the picture below (a small black area on the left side of the screen).

However, if the application is run a few minutes after system login, the image display is OK (not small black area on the left of the screen).

[img]c:\cksim\DSC00127.JPG[/img]

Anyone has the same encounter ?

Thanks in advance.

Please upload the pictures to a web site and post http url. The fact, that your picture is on your hard drive at c:\cksim\DSC00127.JPG does not help much.

Hi AntiSullin,

Any websites to recommend for photos upload ?

I do not know of any at the moment.

Thanks.

For example:
http://imageshack.us/

Actually, google knows everything:
http://www.google.com/search?q=free+image+hosting

Hi AntiSullin,

Image is at




Any idea on the possible causes of the overwriting ?

Thanks in advance.

I've seen similar picture, when the LCD is switched from palette-based mode (that requires much less space in SRAM) to full-color mode and the video memory is not cleared or reorganized. It seems like your picture data is on top rows of the LCD and the rest is just empty SRAM.
If you're using linux kernel bundled with the EK, then that old linux 2.6.15 (if i'm not mistaken) was very buggy - the LCD driver was not stable at all then. Pull a newer kernel (2.6.22 if you want latest stable, or 2.6.23-rc) and apply the latest AT91 patches from http://maxim.org.za/at91_26.html , compile, install and enjoy.

Hi AntiSullin,

FYI, I am using 2.6.21, not the one that came with the EK board.

You may ignore the info displayed as that picture is correct.

However, at the left hand edge of the screen, you will see a small black square area (which is NOT part of the picture) is being displayed.

Do you think this small black area can be resolved by the latest kernel ?

FYI, if the same picture is being displayed a few minutes after system login, the black area will disappear and the correct picture will be seen.

Thanks in advance.

Sry, misunderstood the problem.
Never seen that black square. Does it happen on a single device or have you tried more devices?

Hi AntiSullin,

Yes, it happens on another display device too.

The scenario is as follows:

1) On kernel bootup, the Linux Penguin logo appears
2) After logon, if the image is displayed immediately, the black square area will apeear.
3) If image is displayed after the 'Linux logo' has gone off by itself (after some time), then the image display will be fine (no black square)


One question. Any idea what causes the Linux logo to disappear by itself after some time ?


Thanks in advance

Something overwrites the framebuffer?
Are you keeping your FB in the internal SRAM? Maybe you have some kind of wrong pointer issue in another driver, that just overwrites that region?
I was using the 2.6.21.2+maxim.org.ua patchset in my last set of devices (custom boards with sam9261) and I had no problems with LCD.

Hi AntiSullin,

The buffer on the EK board is using internal SRAM for 320x240 display.

I did not have any drivers of my own.

Really got no idea what is happening.

Best Regards.

Sim CK