Port xf86-video-ast to Openpower

[yu]

Dear Maintainers,


I have a Tyan TN71-BP012 power8 server, and its graphic is  Aspeed AST2400.
http://tyan.com/Barebones_TN71-BP012_BSP012T71V14HR-4T-3

Recently I test Ubuntu 15.10 ppc64el on it, the kernel ast driver
works OK, but when test X, I found that the ast_drv.so build from the
xf86-video-ast can not work, here is the error message from X:

[  7498.243] (II) LoadModule: "ast"
[  7498.244] (II) Loading /usr/lib/xorg/modules/drivers/ast_drv.so
[  7498.244] (EE) Failed to load
/usr/lib/xorg/modules/drivers/ast_drv.so:
/usr/lib/xorg/modules/drivers/ast_drv.so: undefined symbol: ioBase
[  7498.244] (II) UnloadModule: "ast"
[  7498.244] (II) Unloading ast
[  7498.244] (EE) Failed to load module "ast" (loader failed, 7)

I searched the "ioBase", it is defined in the compiler.h under the
MACRO "__powerpc__", so I just change the MACRO to let the driver can
be load, then error again:

[ 26963.956] (WW) Falling back to old probe method for ast
[ 26963.956] (--) Assigning device section with no busID to primary device
[ 26963.956] (--) Assigning device section with no busID to primary device
[ 26963.956] (WW) AST: More than one matching Device section found:
Autoconfigured Video Device ast
[ 26963.956] (--) Chipset ASPEED Graphics Family found
[ 26963.956] (EE) ast: The PCI device 0x2000 at 07 at 01:00:0 has a
kernel module claiming it.
[ 26963.956] (EE) ast: This driver cannot operate until it has been unloaded.

So I just comment the "pci_device_has_kernel_driver" in ast_driver.c
to let the probe continue, then error again:

[ 22795.892] (II) AST(0): Creating default Display subsection in Screen section
        "Default Screen Section" for depth/fbbpp 24/32
[ 22795.892] (==) AST(0): Depth 24, (--) framebuffer bpp 32
[ 22795.892] (==) AST(0): Using gamma correction (1.0, 1.0, 1.0)
[ 22795.892] (==) AST(0): RGB weight 888
[ 22795.892] (==) AST(0): Default visual is TrueColor
[ 22795.892] (--) AST(0): Chipset: "ASPEED Graphics Family"
[ 22795.892] (II) AST(0): Linear framebuffer at 0x82000000
[ 22795.893] (II) AST(0): IO registers at addr 0x81800000
[ 22795.893] (EE) AST(0): Map Memory Map IO Failed


It seems that the xf86-video-ast driver is for a 32bit system? is
there other X driver for the power8 machine using AST chips?

BTW: The xf86-video-vesa can't work on the machine either, the error
message is also "undefined symbol: ioBase".

cheers

Yu