[SeaBIOS] [coreboot] i915 status on x60.

[Denis 'GNUtoo' Carikli]

On Sun, 3 Mar 2013 14:01:35 +0100
Denis 'GNUtoo' Carikli <GNUtoo at no-log.org> wrote:
> So here's the code:
> int dspbase = (plane == 0 ? DSPABASE : DSPBBASE);
> [...]
> int dspstride = (plane == 0) ? DSPASTRIDE : DSPBSTRIDE;
> [...]
> Stride = pScrn->displayWidth * pI830->cpp;
> [...]
> OUTREG(dspstride, Stride);
> [...]
> OUTREG(dspbase, Start + Offset);
> 
> The problem is how to replace Start + Offset, the code is
> quite complicated and I can't probably run it since it probably
> requires an old userspace.

So I followed a bit the code but gave up yesterday night(very late)
here:
/* Allocate aperture space for the given size and alignment, and
returns the
 * memory allocation.
 *
 * Allocations are a minimum of a page, and will be at least
page-aligned.
 */
static i830_memory *
i830_allocate_aperture(ScrnInfoPtr pScrn, const char *name,
                       unsigned long size, unsigned long pitch,
                       unsigned long alignment, int flags,
                       enum tile_format tile_format)
{
[...]
    for (scan = pI830->memory_list; scan->next != NULL; scan =
    scan->next) {
        mem->offset = ROUND_TO(scan->end, alignment);
        if ((flags & NEED_PHYSICAL_ADDR) && mem->offset <
    pI830->stolen_size) {
            /* If the allocation is entirely within stolen memory, and
    we're
             * able to get the physical addresses out of the GTT and
    check that
             * it's contiguous (it ought to be), then we can do our
    physical
             * allocations there and not bother the kernel about it.
    This
             * helps avoid aperture fragmentation from our physical
             * allocations.
             */
            mem->bus_addr = i830_get_stolen_physical(pScrn, mem->offset,
                                                     mem->size);

            if (mem->bus_addr == ((uint64_t)-1)) {
                /* Move the start of the allocation to just past the
            end of
                 * stolen memory.
                 */
                mem->offset = ROUND_TO(pI830->stolen_size, alignment);
            }
        }
        if ((flags & NEED_NON_STOLEN) && mem->offset <
            pI830->stolen_size) {
            mem->offset = ROUND_TO(pI830->stolen_size, alignment);
        }

        mem->end = mem->offset + size;
        if (flags & ALIGN_BOTH_ENDS)
            mem->end = ROUND_TO(mem->end, alignment);
        if (mem->end <= scan->next->offset)
            break;
    }

which is called by i830_allocate_memory(in i830_memory.c) which is
called by(in i830_allocate_2d_memory in i830_memory.c) :

pI830->front_buffer =
    i830_allocate_framebuffer(pScrn, pI830, &pI830->FbMemBox,
FALSE);

Then we have in i830PipeSetBase(in i830_display.c):
    Start = pI830->front_buffer->offset;


For the offset we have in the same file, same function:
  Offset = ((y * pScrn->displayWidth + x) * pI830->cpp);
I don't know what does x and y represents, maybe they are 0?

Denis.
So I followed a bit the code but gave up yesterday night(very late)
here:
/* Allocate aperture space for the given size and alignment, and
returns the
 * memory allocation.
 *
 * Allocations are a minimum of a page, and will be at least
page-aligned.
 */
static i830_memory *
i830_allocate_aperture(ScrnInfoPtr pScrn, const char *name,
                       unsigned long size, unsigned long pitch,
                       unsigned long alignment, int flags,
                       enum tile_format tile_format)
{
[...]
    for (scan = pI830->memory_list; scan->next != NULL; scan =
    scan->next) {
        mem->offset = ROUND_TO(scan->end, alignment);
        if ((flags & NEED_PHYSICAL_ADDR) && mem->offset <
    pI830->stolen_size) {
            /* If the allocation is entirely within stolen memory, and
    we're
             * able to get the physical addresses out of the GTT and
    check that
             * it's contiguous (it ought to be), then we can do our
    physical
             * allocations there and not bother the kernel about it.
    This
             * helps avoid aperture fragmentation from our physical
             * allocations.
             */
            mem->bus_addr = i830_get_stolen_physical(pScrn, mem->offset,
                                                     mem->size);

            if (mem->bus_addr == ((uint64_t)-1)) {
                /* Move the start of the allocation to just past the
            end of
                 * stolen memory.
                 */
                mem->offset = ROUND_TO(pI830->stolen_size, alignment);
            }
        }
        if ((flags & NEED_NON_STOLEN) && mem->offset <
            pI830->stolen_size) {
            mem->offset = ROUND_TO(pI830->stolen_size, alignment);
        }

        mem->end = mem->offset + size;
        if (flags & ALIGN_BOTH_ENDS)
            mem->end = ROUND_TO(mem->end, alignment);
        if (mem->end <= scan->next->offset)
            break;
    }

which is called by i830_allocate_memory(in i830_memory.c) which is
called by(in i830_allocate_2d_memory in i830_memory.c) :

pI830->front_buffer =
    i830_allocate_framebuffer(pScrn, pI830, &pI830->FbMemBox,
FALSE);

Then we have in i830PipeSetBase(in i830_display.c):
    Start = pI830->front_buffer->offset;


For the offset we have in the same file, same function:
  Offset = ((y * pScrn->displayWidth + x) * pI830->cpp);
I don't know what does x and y represents, maybe they are 0?

Denis.