| Message ID | 20110623114536.GA14011@linux-mips.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Thu, Jun 23, 2011 at 07:10:29AM -0500, Kumar Gala wrote: > > (Adding the PPC folks to cc.) > > > > A "git grep -w PAGE_KERNEL_NOCACHE arch/powerpc/" doesn't find anything so > > I don't think the driver will build there. I don't have a PPC toolchain > > to verify that. > > I can verify it fails on PPC as well: > > drivers/staging/comedi/drivers.c: In function 'comedi_buf_alloc': > drivers/staging/comedi/drivers.c:505:37: error: 'PAGE_KERNEL_NOCACHE' undeclared (first use in this function) > drivers/staging/comedi/drivers.c:505:37: note: each undeclared identifier is reported only once for each function it appears in > > However, we do have a #define for PAGE_KERNEL_NC. Do you think this driver in it's current stage is so valuable that some ifdefery to get it to work on PPC is the way to go? IA-64 has PAGE_KERNEL_UC, so basically the same question for IA-64, too. But preferably the driver should be sorted out properly and until the v1 of my patch which disables it on all architectures that don't provide a PAGE_KERNEL_NOCACHE definition will do just fine. Ralf -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jun 23, 2011 at 13:45, Ralf Baechle <ralf@linux-mips.org> wrote: > On architectures that don't define PAGE_KERNEL_NOCACHE, the Comedi driver turns > into tragedy: > > CC [M] drivers/staging/comedi/drivers.o > drivers/staging/comedi/drivers.c: In function ‘comedi_buf_alloc’: > drivers/staging/comedi/drivers.c:505:41: error: ‘PAGE_KERNEL_NOCACHE’ undeclared (first use in this function) > drivers/staging/comedi/drivers.c:505:41: note: each undeclared identifier is rep orted only once for each function it appears in > make[3]: *** [drivers/staging/comedi/drivers.o] Error 1 > > Restrict the driver to only those architectures that define PAGE_KERNEL_NOCACHE. > > PAGE_KERNEL_NOCACHE is a kludge - some system architectures such as SGI IP27 > are even uable to offer uncached operation - at least in the way an unwitting > driver might assume. I haven't looked in details how the driver is using > the area vmaped with PAGE_KERNEL_NOCACHE but maybe doing it XFS-style using > cached memory and the flush_kernel_vmap_range / invalidate_kernel_vmap_range > APIs in conjunction with the DMA API is a practical alternative. > > Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> If only to get m68k/allmodconfig going again (hmm, there's another staging driver preventing a green light). 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 -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jun 23, 2011 at 06:01:47PM +0200, Geert Uytterhoeven wrote: > If only to get m68k/allmodconfig going again (hmm, there's another > staging driver > preventing a green light). I ran into this doing an allyesconfig. Allyesconfig has one disadvantage, for choice it will only select the first or default option which means that option gets exercised well and all the other options not at all. On MIPS that'd be IP22, 32-bit, R4x00, big endian, 4K pages, no multithreading, 250Hz. Make randconfig disables lots of things so often misses the opportunity to trigger some issues. I'd really want an "make allrandconfig" which enables as many options as possible but picks a random one from choice statements, something like that. Ralf -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2011-06-23 at 13:02 +0100, Ralf Baechle wrote: > On Thu, Jun 23, 2011 at 12:53:36PM +0100, Martyn Welch wrote: > > > On 23/06/11 12:45, Ralf Baechle wrote: > > > On architectures that don't define PAGE_KERNEL_NOCACHE, the Comedi driver turns > > > into tragedy: > > > > > > CC [M] drivers/staging/comedi/drivers.o > > > drivers/staging/comedi/drivers.c: In function ‘comedi_buf_alloc’: > > > drivers/staging/comedi/drivers.c:505:41: error: ‘PAGE_KERNEL_NOCACHE’ undeclared (first use in this function) > > > drivers/staging/comedi/drivers.c:505:41: note: each undeclared identifier is rep orted only once for each function it appears in > > > make[3]: *** [drivers/staging/comedi/drivers.o] Error 1 > > > > > > Restrict the driver to only those architectures that define PAGE_KERNEL_NOCACHE. > > > > > > PAGE_KERNEL_NOCACHE is a kludge - some system architectures such as SGI IP27 > > > are even uable to offer uncached operation - at least in the way an unwitting > > > driver might assume. I haven't looked in details how the driver is using > > > the area vmaped with PAGE_KERNEL_NOCACHE but maybe doing it XFS-style using > > > cached memory and the flush_kernel_vmap_range / invalidate_kernel_vmap_range > > > APIs in conjunction with the DMA API is a practical alternative. > > > > > > Signed-off-by: Ralf Baechle <ralf@linux-mips.org> > > > > > > drivers/staging/comedi/Kconfig | 1 + > > > 1 files changed, 1 insertions(+), 0 deletions(-) > > > > > > diff --git a/drivers/staging/comedi/Kconfig b/drivers/staging/comedi/Kconfig > > > index 1502d80..bccdc12 100644 > > > --- a/drivers/staging/comedi/Kconfig > > > +++ b/drivers/staging/comedi/Kconfig > > > @@ -2,6 +2,7 @@ config COMEDI > > > tristate "Data acquisition support (comedi)" > > > default N > > > depends on m > > > + depends on BROKEN || FRV || M32R || MN10300 || SUPERH || TILE || X86 > > > > I'm sure I got comedi to compile on a 32-bit PPC board not that long ago. Has > > something changed, or is this just not an exhaustive list? It went away. There's a proper API (pgprot_noncached), but it depends what this is used for and it's likely to be broken anyways... what is that driver trying to map non-cached ? Cheers, Ben. > (Adding the PPC folks to cc.) > > A "git grep -w PAGE_KERNEL_NOCACHE arch/powerpc/" doesn't find anything so > I don't think the driver will build there. I don't have a PPC toolchain > to verify that. > > Ralf > -- > To unsubscribe from this list: send the line "unsubscribe linux-arch" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Ralf, On Thu, 23 Jun 2011 12:45:37 +0100 Ralf Baechle <ralf@linux-mips.org> wrote: > > On architectures that don't define PAGE_KERNEL_NOCACHE, the Comedi driver turns > into tragedy: > > CC [M] drivers/staging/comedi/drivers.o > drivers/staging/comedi/drivers.c: In function ‘comedi_buf_alloc’: > drivers/staging/comedi/drivers.c:505:41: error: ‘PAGE_KERNEL_NOCACHE’ undeclared (first use in this function) > drivers/staging/comedi/drivers.c:505:41: note: each undeclared identifier is rep orted only once for each function it appears in > make[3]: *** [drivers/staging/comedi/drivers.o] Error 1 > > Restrict the driver to only those architectures that define PAGE_KERNEL_NOCACHE. > > PAGE_KERNEL_NOCACHE is a kludge - some system architectures such as SGI IP27 > are even uable to offer uncached operation - at least in the way an unwitting > driver might assume. I haven't looked in details how the driver is using > the area vmaped with PAGE_KERNEL_NOCACHE but maybe doing it XFS-style using > cached memory and the flush_kernel_vmap_range / invalidate_kernel_vmap_range > APIs in conjunction with the DMA API is a practical alternative. > > Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Since Greg is on vacation, I will add this patch to my fixes tree in linux-next until a better fix comes along (if there is one).
diff --git a/drivers/staging/comedi/Kconfig b/drivers/staging/comedi/Kconfig index 1502d80..bccdc12 100644 --- a/drivers/staging/comedi/Kconfig +++ b/drivers/staging/comedi/Kconfig @@ -2,6 +2,7 @@ config COMEDI tristate "Data acquisition support (comedi)" default N depends on m + depends on BROKEN || FRV || M32R || MN10300 || SUPERH || TILE || X86 ---help--- Enable support a wide range of data acquisition devices for Linux.
On architectures that don't define PAGE_KERNEL_NOCACHE, the Comedi driver turns into tragedy: CC [M] drivers/staging/comedi/drivers.o drivers/staging/comedi/drivers.c: In function ‘comedi_buf_alloc’: drivers/staging/comedi/drivers.c:505:41: error: ‘PAGE_KERNEL_NOCACHE’ undeclared (first use in this function) drivers/staging/comedi/drivers.c:505:41: note: each undeclared identifier is rep orted only once for each function it appears in make[3]: *** [drivers/staging/comedi/drivers.o] Error 1 Restrict the driver to only those architectures that define PAGE_KERNEL_NOCACHE. PAGE_KERNEL_NOCACHE is a kludge - some system architectures such as SGI IP27 are even uable to offer uncached operation - at least in the way an unwitting driver might assume. I haven't looked in details how the driver is using the area vmaped with PAGE_KERNEL_NOCACHE but maybe doing it XFS-style using cached memory and the flush_kernel_vmap_range / invalidate_kernel_vmap_range APIs in conjunction with the DMA API is a practical alternative. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> drivers/staging/comedi/Kconfig | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html