Modesetting
We know libxenon sets graphics modes by writing a complete Ana dump to Ana memory and writing some values to the GPU registers. The registers affected and the information that gets written is the following:
total_width, hsync_offset, real_active_width, total_height,
vsync_offset, active_height, width, height,
is_progressive = 0 for non progressive modes, 1 for progressive modes.
rgb = 1, only declared on the modes used through VGA.
composite_sync=1, only declared on the PAL/NTSC non progressive modes.
interlace_factor is set to 1 when mode is progressive and 2 when it is not.
FB_BASE is a constant for the framebuffer base address on libxenon, but we
get different addresses on the GPU dumps.
These are the addresses that get that variables written at some stage of the initialization, in the order libxenon write them. I have take out the addresses that get fixed values written. As you can see, some addresses get written more than one time on the initialization process. Following are the values of the GPU dumps we currently own. We need to find a way to know if these dumps are valid as some values differ drastically from what we can read on libxenon's xenos.c and, if they are valid, why the are not the values expected.
0x6000, mode->total_width - 1
1024x768: 0x0000053f
1280x1024: 0x00000697
1280x720: 0x00000671
1920x1080: 0x0000081f
0x6010, mode->total_height - 1
1024x768: 0x00000325
1280x1024: 0x00000429
1280x720: 0x000002ed
1920x1080: 0x00000456
0x6004, (mode->hsync_offset << 16) | (mode->real_active_width + mode->hsync_offset)
1024x768: 0x00eb04eb
1280x1024: 0x01250625
1280x720: 0x00c705c7
1920x1080: 0x002d07ad
0x6014, (mode->vsync_offset << 16) | (mode->active_height * interlace_factor + mode->vsync_offset)
1024x768: 0x00230323
1280x1024: 0x00290429
1280x720: 0x001902e9
1920x1080: 0x001c0454
0x6030, mode->is_progressive ? 0 : 1
It is 0x00000000 on all the dumps.
0x6120, mode->width
This address gets rewritten later.
0x6134, mode->width
1024x768: 0x000003c0
1280x1024: 0x000003c0
1280x720: 0x00000500
1920x1080: 0x00000360
0x6138, mode->active_height * interlace_factor
This address gets rewritten later.
0x6110, FB_BASE
1024x768: 0x1f78e000
1280x1024: 0x1f78e000
1280x720: 0x1f6a8000
1920x1080: 0x01c5b000
0x6120, mode->width
1024x768: 0x000003c0
1280x1024: 0x000003c0
1280x720: 0x00000500
1920x1080: 0x00000360
0x2840, FB_BASE
0x2844, mode->width
I don't know what hardware is in charge on this memory addresses
0x6584, (mode->width << 16) | (mode->active_height * interlace_factor)
This address gets rewritten later.
0x65e8, (mode->width >> 2) - 1
This address gets rewritten later.
0x6528, mode->is_progressive ? 0 : 1
It is 0x00000000 on all the dumps.
0x6584, (mode->width << 16) | (mode->height * interlace_factor)
1024x768: 0x040002d0
1280x1024: 0x040002d0
1280x720: 0x050002d0
1920x1080: 0x035401e0
0x65e8, (mode->width / 4) - 1
1024x768: 0x000000ff
1280x1024: 0x000000ff
1280x720: 0x0000013f
1920x1080: 0x000000d4
0x6434, mode->width
It is 0x00000000 in all dumps (!?)
0x6138, mode->height * interlace_factor
1024x768: 0x000002d0
1280x1024: 0x000002d0
1280x720: 0x000002d0
1920x1080: 0x000001e0