640x480 8bppx and DVI_SYMBOLS_PER_WORD=1 half right

[mlorenzati]

I'm testing 8bits per pixel (RGB332) in a 640x240 buffer mode using DVI_SYMBOLS_PER_WORD=1

uint8_t framebuf[FRAME_HEIGHT][FRAME_WIDTH];

in core 1 main I'm running the dvi
void __not_in_flash_func(core1_main)() {
	dvi_register_irqs_this_core(&dvi0, DMA_IRQ_0);
	dvi_start(&dvi0);
        dvi_scanbuf_main_8bpp(&dvi0);
	__builtin_unreachable();
}

video gfx buffer is properly set, but encoding appears to be doing half the screen, what could be wrong?

[mlorenzati]

Code for reference
CMakeList, enabling 1 symbol per word
target_compile_definitions(graphicsTest PRIVATE DVI_VERTICAL_REPEAT=2 DVI_SYMBOLS_PER_WORD=1 )

#define FRAME_WIDTH 640
uint8_t framebuf[FRAME_HEIGHT][FRAME_WIDTH];
#endif

#define REFRESH_RATE 50
#define VREG_VSEL VREG_VOLTAGE_1_20
#define DVI_TIMING dvi_timing_640x480p_60hz

struct dvi_inst dvi0;

static uint hdmi_scanline = 2;

void __not_in_flash_func(core1_main)() {
	dvi_register_irqs_this_core(&dvi0, DMA_IRQ_0);
	dvi_start(&dvi0);
	dvi_scanbuf_main_8bpp(&dvi0);
	__builtin_unreachable();
}

static inline void core1_scanline_callback() {
	uint8_t *bufptr;
	while (queue_try_remove_u32(&dvi0.q_colour_free, &bufptr));
	bufptr = &framebuf[hdmi_scanline][0];
	queue_add_blocking_u32(&dvi0.q_colour_valid, &bufptr);
	if (++hdmi_scanline >= FRAME_HEIGHT) {
    	hdmi_scanline = 0;
	}
}

int main() {
	vreg_set_voltage(VREG_VSEL);
	sleep_ms(10);

	// Run system at TMDS bit clock
	set_sys_clock_khz(DVI_TIMING.bit_clk_khz, true);
	
	dvi0.timing = &DVI_TIMING;
	dvi0.ser_cfg = DVI_DEFAULT_SERIAL_CONFIG;
	dvi0.scanline_callback = core1_scanline_callback;
	dvi_init(&dvi0, next_striped_spin_lock_num(), next_striped_spin_lock_num());
	uint8_t *bufptr;
	
	queue_add_blocking_u32(&dvi0.q_colour_valid, &bufptr);
	bufptr += FRAME_WIDTH;
	queue_add_blocking_u32(&dvi0.q_colour_valid, &bufptr);

	printf("Core 1 start\n");
	multicore_launch_core1(core1_main);
	
	//Here I prepare a graphic on the buffer
	while (1)
	{
		sleep_ms(1000);
	}
	__builtin_unreachable();
}

[mlorenzati]

Half screen shows the image properly, the other half has some data right but scrambled

[mlorenzati]

Whats confusing for me is that RGB16 version, if I play around with DVI_SYMBOLS_PER_WORD I can go full or half resolution, on RGB8 it fails

[mlorenzati]

Could you add @Wren6991 an example of dvi_scanbuf_main_8bpp with DVI_SYMBOLS_PER_WORD=1?

[mlorenzati]

From what I could test, the only color that it's not properly coded is red, in the second half

[mlorenzati]

I think I fixed it: I just added a DVI_SYMBOLS_PER_WORD==1 comparisson to leftshift encode.
I don't have the full understanding of the issue to ensure this is a proper fix, but it resolves my problem

void __not_in_flash_func(tmds_encode_data_channel_8bpp)(const uint32_t *pixbuf, uint32_t *symbuf, size_t n_pix, uint channel_msb, uint channel_lsb) {
 //...
	if (require_lshift || DVI_SYMBOLS_PER_WORD==1)	
		tmds_encode_loop_8bpp_leftshift(pixbuf, symbuf, n_pix, require_lshift);
	else
		tmds_encode_loop_8bpp(pixbuf, symbuf, n_pix);
//...
}