Messages in this thread | | | Date | Mon, 15 Dec 2014 15:10:38 +0100 | Subject | Re: [PATCH/RESEND] [media] VIDEO_CAFE_CCIC should select VIDEOBUF2_DMA_SG | From | Geert Uytterhoeven <> |
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Hi Jon,
On Mon, Dec 15, 2014 at 3:04 PM, Jonathan Corbet <corbet@lwn.net> wrote: > On Mon, 15 Dec 2014 14:55:37 +0100 > Geert Uytterhoeven <geert@linux-m68k.org> wrote: > >> If VIDEO_CAFE_CCIC=y, but VIDEOBUF2_DMA_SG=m: >> >> drivers/built-in.o: In function `mcam_v4l_open': >> mcam-core.c:(.text+0x1c2e81): undefined reference to `vb2_dma_sg_memops' >> mcam-core.c:(.text+0x1c2eb0): undefined reference to `vb2_dma_sg_init_ctx' >> drivers/built-in.o: In function `mcam_v4l_release': >> mcam-core.c:(.text+0x1c34bf): undefined reference to `vb2_dma_sg_cleanup_ctx' > > I've been mildly resistant to this because I've never figured out how > such a configuration can come about. The Cafe chip only appeared in the > OLPC XO-1 and cannot even come close to doing S/G I/O. So this patch > robs a bit of memory for no use on a platform that can ill afford it.
If the driver cannot do SG, perhaps this block should be removed from drivers/media/platform/marvell-ccic/mcam-core.h?
#if IS_ENABLED(CONFIG_VIDEOBUF2_DMA_SG) #define MCAM_MODE_DMA_SG 1 #endif
Oh, this seems to be a reason for the breakage, too: IS_ENABLED() evaluates to true for modular options...
> OTOH, the number of people building contemporary kernels for the XO-1 has > got to be pretty small. So, in the interest of mollifying randconfig > users out there, you can add my: > > Acked-by: Jonathan Corbet <corbet@lwn.net>
Thanks!
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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