Setting a custom modeline with incorrect syntax crashes the board

[tdaede]

H2U 00:00:05>m custom 
Parsing custom mode...
Failed to set custom mode - values out of range.
Aborted.

It shouldn't require resetting the board if a typo is made.

[mithro]

@tdaede Agreed that it shouldn't cause the system to lock up. Want to see if you can fix it?

The parsing code is at

HDMI2USB-litex-firmware/firmware/ci.c

Lines 750 to 875 in 585091a

	static void video_mode_custom(char* str)
	{
	wprintf("Parsing custom mode...\n");
	char* token;
	// Modeline "String description" Dot-Clock HDisp HSyncStart HSyncEnd HTotal VDisp VSyncStart VSyncEnd VTotal [options]
	// $ xrandr --newmode "1280x1024_60.00" 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync
	// Based on code from http://cgit.freedesktop.org/xorg/app/xrandr/tree/xrandr.c#n3101
	NEXT_TOKEN_OR_RETURN(str, token);
	char* dotClockInt = get_token_generic(&token, '.');
	char* dotClockDec = get_token(&token);
	if (!dotClockInt || !dotClockDec) return;
	unsigned int dotClock = (atoi(dotClockInt) * 100) + atoi(dotClockDec);
	NEXT_TOKEN_OR_RETURN(str, token);
	unsigned int width = atoi(token);
	NEXT_TOKEN_OR_RETURN(str, token);
	unsigned int hSyncStart = atoi(token);
	NEXT_TOKEN_OR_RETURN(str, token);
	unsigned int hSyncEnd = atoi(token);
	NEXT_TOKEN_OR_RETURN(str, token);
	unsigned int hTotal = atoi(token);
	NEXT_TOKEN_OR_RETURN(str, token);
	unsigned int height = atoi(token);
	NEXT_TOKEN_OR_RETURN(str, token);
	unsigned int vSyncStart = atoi(token);
	NEXT_TOKEN_OR_RETURN(str, token);
	unsigned int vSyncEnd = atoi(token);
	NEXT_TOKEN_OR_RETURN(str, token);
	unsigned int vTotal = atoi(token);
	unsigned int modeFlags = EDID_DIGITAL; // Always Digital Separate
	while (*str != '\0') {
	token = get_token(&str);
	if (*token == '\0' && *str == '\0') break;
	int f;
	for (f = 0; timing_mode_flags[f].string; f++)
	if (strcasecmp(timing_mode_flags[f].string, token) == 0)
	break;
	if (!timing_mode_flags[f].string) {
	if (*token != '\0') {
	wprintf("Skipping flag: %s\n", token);
	continue;
	}
	break;
	}
	modeFlags |= timing_mode_flags[f].flag;
	}
	/*
	-------------------> Time ------------->
	+-------------------+
	Video | Blanking | Video
	| |
	----(a)--------->|<-------(b)------->|
	| |
	| +-------+ |
	| | Sync | |
	| | | |
	|<-(c)->|<-(d)->| |
	| | | |
	----(1)--------->| | | |
	----(2)----------------->| | |
	----(3)------------------------->| |
	----(4)----------------------------->|
	| | | |
	-----------------\ /--------
	| |
	\-------\ /---/
	| |
	\-------/
	(a) - h_active
	(b) - h_blanking
	(c) - h_sync_offset
	(d) - h_sync_width
	(1) - HDisp / width
	(2) - HSyncStart
	(3) - HSyncEnd
	(4) - HTotal
	*/
	if (hTotal <= hSyncEnd || hSyncEnd <= hSyncStart ||
	hSyncStart <= width || vTotal <= vSyncEnd ||
	vSyncEnd <= vSyncStart || vSyncStart <= height) {
	wprintf("Failed to set custom mode - values out of range.\n");
	}
	struct video_timing* mode = processor_get_custom_mode();
	// 640x480 @ 75Hz (VESA) hsync: 37.5kHz
	// Modeline "String des" Dot-Clock HDisp HSyncStart HSyncEnd HTotal VDisp VSyncStart VSyncEnd VTotal [options]
	// ModeLine "640x480" 31.5 640 656 720 840 480 481 484 500
	// 16 64 <200 1 3 <20
	mode->pixel_clock = dotClock;
	mode->h_active = width;
	mode->h_blanking = hTotal - width;
	mode->h_sync_offset = hSyncStart - hTotal;
	mode->h_sync_width = hSyncEnd - hSyncStart;
	mode->v_active = height;
	mode->v_blanking = vTotal - height;
	mode->v_sync_offset = vSyncStart - height;
	mode->v_sync_width = vSyncEnd - vSyncStart;
	mode->flags = modeFlags;
	processor_set_custom_mode();
	wprintf("Custom video mode set.\n");
	}