Subject: Re: [PATCH] PPC : missing request_dma and free_dma on PPC 405

From: Mathieu Desnoyers <[email-masked]>
Date: Thu, 8 Feb 2007 10:31:51 -0500

* Kumar Gala ([email-masked]) wrote:
>=20
> On Feb 7, 2007, at 5:48 PM, Mathieu Desnoyers wrote:
>=20
> >PPC : missing request_dma and free_dma on PPC 405
> >
> >The solution I have found to correct this linking error for modules
> >that use DMA is to allow 4xx to select GENERIC_ISA_DMA in arch/ppc/=20
> >Kconfig.
> >It applies on 2.6.20.
> >
> >Signed-off-by: Mathieu Desnoyers <[email-masked]>
>=20
> Are you actually using request_dma/free_dma?
>=20
> The reason this was Kconfig'd this way is that ISA_DMA doesn't make =20
> sense on 4xx or the majority of PPC's because of the lack of an ISA bus.
>=20

No, but, in the configuration I tried to build, the following macro :
include/asm-powerpc/vga.h:#define VGA_MAP_MEM(x,s) (x + vgacon_remap_base)
is used by drivers/video/console/vgacon.c which can be compiled as a
module (drivers/video/vga16fb.ko) for PPC 405.

Maybe the right solution would be to make FB_VGA16, VGA_CONSOLE and
MDA_CONSOLE depend on GENERIC_ISA_DMA (or disable them for 4xx and 8xx).

in drivers/video/console/Kconfig
VGA_CONSOLE already uses :
depends on !ARCH_ACORN && !ARCH_EBSA110 && !4xx && !8xx && !SPARC &&
    !M68K && !PARISC && !FRV && !ARCH_VERSATILE && !SUPERH

MDA_CONSOLE
depends on !M68K && !PARISC && ISA (depending on ISA seems to make it
OK)

in drivers/video/Kconfig
FB_VGA16
depends on FB && (X86 || PPC)
here we should probably change it for :
depends on FB && (X86 || PPC64 || (PPC32 && GENERIC_ISA_DMA))

Signed-off-by: Mathieu Desnoyers <[email-masked]>

--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -488,7 +488,7 @@ config FB_IMSTT
=20
 config FB_VGA16
 	tristate "VGA 16-color graphics support"
-	depends on FB && (X86 || PPC)
+	depends on FB && (X86 || PPC64 || (PPC32 && GENERIC_ISA_DMA))
 	select FB_CFB_FILLRECT
 	select FB_CFB_COPYAREA
 	select FB_CFB_IMAGEBLIT
--=20
Mathieu Desnoyers
Computer Engineering Graduate Student, =C9cole Polytechnique de Montr=E9al
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68