am335x android maximum framebuffer size

Mickael Leforestier

Hi,

I am facing a problem when I try to use a screen with this size :

1366*768

I am in 32 bits / pixel.

I have a Memory allocation failed for fb_info for this size. Someone can explains in wich condition the am335x can display something at 2048*2048 please ?

Thanks in advance

Regards,

Mickael

over 9 years ago

0 Adeneo Embedded support team over 9 years ago

Mastermind 9310 points

Hi Mickael,

The LCD controller supports only up to 24-bit data output but should be able to support the resolution of 1366x768.
Could you try to set the data output to 24-bits instead of 32?

0 Mickael Leforestier over 9 years ago in reply to Adeneo Embedded support team

Intellectual 700 points

Hi !

Thanks for your answer, unfortunately I have still the problem :

1] [<c0042620>] (warn_slowpath_null+0x0/0x34) from [<c00a607c>] (__alloc_pages_nodemask+0x1b4/0x68c)
[    1.206237] [<c00a5ec8>] (__alloc_pages_nodemask+0x0/0x68c) from [<c0019ba0>] (__dma_alloc+0xec/0x338)
[    1.216003] [<c0019ab4>] (__dma_alloc+0x0/0x338) from [<c001a520>] (dma_alloc_coherent+0x64/0x70)
[    1.225280] [<c001a4bc>] (dma_alloc_coherent+0x0/0x70) from [<c059d864>] (fb_probe+0xaf8/0xb54)
[    1.234375] r7:df29c654 r6:df29d808 r5:c08202e8 r4:01002000
[    1.240325] [<c059cd6c>] (fb_probe+0x0/0xb54) from [<c02d4140>] (platform_drv_probe+0x28/0x2c)
[    1.249328] [<c02d4118>] (platform_drv_probe+0x0/0x2c) from [<c02d2c04>] (driver_probe_device+0xa0/0x1bc)
[    1.259338] [<c02d2b64>] (driver_probe_device+0x0/0x1bc) from [<c02d2e0c>] (__device_attach+0x4c/0x50)
[    1.269073] r8:c088def4 r7:00000000 r6:c02d2dc0 r5:df29d808 r4:c081ffec

I change the bpp in the lcd_ctrl_config to 24 as you mentionned.

Regards,

Mickael

0 Adeneo Embedded support team over 9 years ago in reply to Mickael Leforestier

Mastermind 9310 points

Hi Mickael,

Apparently your issue has already been fixed in the following post: e2e.ti.com/.../690610

Can you let me know if that works for you?

Thanks,

0 Mickael Leforestier over 9 years ago in reply to Adeneo Embedded support team

Intellectual 700 points

Hi,

I follow the post, the CONFIG_FORCE_MAX_ZONEORDER was already at 12. I changed the bpp field of lcd_cfg struct to 16 and fields of display_panel to 16 ... I don't have the problem anymore but see lcdc sync lost for the moment.

Regards,

Mickael

0 Adeneo Embedded support team over 9 years ago in reply to Mickael Leforestier

Mastermind 9310 points

Hi Mickael,

We believe that the LCD lost synchronization is generated because of an incorrect settings for the timing with your display. Sadly, we can support only the configuration from the am335x-evm.
Could you check and make sure that the timings are set properly to your panel in your board file? Especially with the modification for the bpp.

0 Mickael Leforestier over 8 years ago in reply to Adeneo Embedded support team

Intellectual 700 points

Hi,

I would like to understand why my screen parameters 1366*768 are not good and gives me "LCDC sync lost". There is a limitation somewhere for this value ?

Thanks in advance

Mickael

0 Adeneo Embedded support team over 8 years ago in reply to Mickael Leforestier

Mastermind 9310 points

Hi Mickael,

I believe the "LCDC sync lost" is not related to the setting of your resolution but in the timings of your display (back/front porch, vsync, ...).
Could you check these values against the datasheet of your display? It should defined in your panel source file (drivers/video/omap2/displays/panel-*)

Also, checking the frequency/signals of the pixclk/vsync/hsync with an oscilloscope could be useful in your case.

0 Mickael Leforestier over 8 years ago in reply to Adeneo Embedded support team

Intellectual 700 points

Hello,

Thanks for your help, there is the reference of the screen : IO140I0028.

There is the value that I put in the da88x-fb.c :

.width = 1366,
.height = 768,
.hfp = 0,
.hbp = 100,
.hsw = 0,
.vfp = 0,
.vbp = 50
.vsw = 0,

Pixel clock is correctly set at 72Mhz as specified in Timing Characteristics tab.

Do you see something wrong ?

Thanks in advance

Mickael

0 Adeneo Embedded support team over 8 years ago in reply to Mickael Leforestier

Mastermind 9310 points

Hi Mickael,
We support only TI AM335x reference platforms and their configurations in this forum. We are unable to support custom hardware effectively.

0 Mickael Leforestier over 8 years ago in reply to Adeneo Embedded support team

Intellectual 700 points

...
Wich configuration have you done in da8xx-fb.c ?

0 Mickael Leforestier over 8 years ago in reply to Mickael Leforestier

Intellectual 700 points

Okay , I tried to set a lot of value in the panel struct, and the only things that I notice is whatever I put in hfp, etc ... Only modification of width/height changes something. When I pass up to 1280. All values failed ... I think Android does something with this values, not ready to play with resolution bigger, and make failed feeder of pictures...

0 Mickael Leforestier over 8 years ago in reply to Mickael Leforestier

Intellectual 700 points

1360 is accepted by the driver, 1366 Not.

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am335x android maximum framebuffer size