[BUG] stm32f746g-disco display examples show garbage

[raiden00pl]

Description / Steps to reproduce the issue

./tools/configure.sh stm32f746g-disco/fb
make -j
nsh> fb
<garbage on the screen>

It should be:

But it is:

On which OS does this issue occur?

[OS: Linux]

What is the version of your OS?

Arch Linux

NuttX Version

nuttx-12.7.0-RC0

Issue Architecture

[Arch: arm]

Issue Area

[Area: Drivers], [Area: OS Components]

Verification

• I have verified before submitting the report.

[raiden00pl]

stm32f746g-disco/nxdemo also broken

[cederom]

We are waiting for LVGL 9.2.1 release lots of fixes incoming and if all works fine we will include it in NuttX 12.7.0 :-)

[raiden00pl]

@cederom @xiaoxiang781216 This issue is not related to LVGL. fb and nxlines examples don't use LVGL, something else is broken.

[cederom]

This seems the same problem as reported by @TimJTi ?

Update: Nope, all problems that Tim had seems to be fixed already in the LVGL upstream :-)

[terry0012]

@raiden00pl can you provide the output log of ‘fb’ ?

we want to check FB driver info first.

[terry0012]

@raiden00pl
I found that output bpp is 24 in boards/arm/stm32f7/stm32f746g-disco/include/board.h
#define BOARD_LTDC_OUTPUT_BPP 24
and gpio settings is using 24bpp as below.

static const uint32_t g_ltdcpins[] =
{
  GPIO_LTDC_R4, GPIO_LTDC_R5, GPIO_LTDC_R6, GPIO_LTDC_R7,
  GPIO_LTDC_G4, GPIO_LTDC_G5, GPIO_LTDC_G6, GPIO_LTDC_G7,
  GPIO_LTDC_B4, GPIO_LTDC_B5, GPIO_LTDC_B6, GPIO_LTDC_B7,
#if BOARD_LTDC_OUTPUT_BPP > 12
  GPIO_LTDC_R3, GPIO_LTDC_G2, GPIO_LTDC_G3, GPIO_LTDC_B3,
#  if BOARD_LTDC_OUTPUT_BPP > 16
  GPIO_LTDC_R2, GPIO_LTDC_B2,
#    if BOARD_LTDC_OUTPUT_BPP > 18
  GPIO_LTDC_R0, GPIO_LTDC_R1, GPIO_LTDC_G0, GPIO_LTDC_G1,
  GPIO_LTDC_B0, GPIO_LTDC_B1,
#    endif
#  endif
#endif
  GPIO_LTDC_VSYNC, GPIO_LTDC_HSYNC, GPIO_LTDC_DE, GPIO_LTDC_CLK
};

But the bpp reported by framebuffer driver is 16, and framebuffer length is also in bpp 16 mode (261120 = 480 * 272 * 2).

CONFIG_STM32F7_LTDC_FB_SIZE=261120
CONFIG_STM32F7_LTDC_L1_CHROMAKEYEN=y
CONFIG_STM32F7_LTDC_L1_CHROMAKEY=0x00000000
CONFIG_STM32F7_LTDC_L1_COLOR=0x00000000
CONFIG_STM32F7_LTDC_L1_RGB565=y

can you check this problem, and try to set BOARD_LTDC_OUTPUT_BPP to 16 and test again ?

[raiden00pl]

@terry0012
BOARD_LTDC_OUTPUT_BPP set to 16 doesn't fix the problem. Here fb output with BOARD_LTDC_OUTPUT_BPP=16:

nsh> fb
VideoInfo:
      fmt: 11
     xres: 480
     yres: 272
  nplanes: 1
PlaneInfo (plane 0):
    fbmem: 0xc0000000
    fblen: 261120
   stride: 960
  display: 0
      bpp: 16
Mapped FB: 0xc0000000
 0: (  0,  0) (480,272)
 1: ( 43, 24) (394,224)
 2: ( 86, 48) (308,176)
 3: (129, 72) (222,128)
 4: (172, 96) (136, 80)
 5: (215,120) ( 50, 32)
Test finished

[terry0012]

I don't have the stm32f746g-disco board, but from the documentation, I can see that its LCD is 24bpp.

should we report 24bpp for framebuffer driver ? @raiden00pl

I have STM32F429-disco, and test fb with RGB565, it show buffer correctly.

[raiden00pl]

@terry0012
Thanks for help. The problem is somewhere in board configuration which was broken long time ago. I didn't find the reason yet, but I'll take care of it. Thanks for your help.