From 4a367f3a9dbf2e7ffcee4702203479809236ee6e Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 9 May 2008 08:06:55 +0200 Subject: x86/PCI: fix broken ISA DMA Rene Herman reported: > commit 8779f2fc3b84ebb6c5181fb13d702e9944c16069 > > "x86: don't try to allocate from DMA zone at first" > > breaks all of ISA DMA. Or all of ALSA ISA DMA at least. All > ISA soundcards are silent following that commit -- no error > messages, everything appears fine, just silence. That patch is buggy. We had an implicit assumption that dev = NULL for ISA devices that require 24bit DMA. The recent work on x86 dma_alloc_coherent() breaks the ISA DMA buffer allocation, which is represented by "dev = NULL" and requires 24bit DMA implicitly. Bisected-by: Rene Herman Signed-off-by: Takashi Iwai Signed-off-by: Ingo Molnar Signed-off-by: Jesse Barnes --- arch/x86/kernel/pci-dma.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 0c37f16b6950..c5ef1af8e79d 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -385,11 +385,13 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &memory)) return memory; - if (!dev) + if (!dev) { dev = &fallback_dev; + gfp |= GFP_DMA; + } dma_mask = dev->coherent_dma_mask; if (dma_mask == 0) - dma_mask = DMA_32BIT_MASK; + dma_mask = (gfp & GFP_DMA) ? DMA_24BIT_MASK : DMA_32BIT_MASK; /* Device not DMA able */ if (dev->dma_mask == NULL) @@ -403,7 +405,7 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, larger than 16MB and in this case we have a chance of finding fitting memory in the next higher zone first. If not retry with true GFP_DMA. -AK */ - if (dma_mask <= DMA_32BIT_MASK) + if (dma_mask <= DMA_32BIT_MASK && !(gfp & GFP_DMA)) gfp |= GFP_DMA32; #endif -- cgit v1.2.2 From 77db9885646f8a88214ea482988d41f8f73630f4 Mon Sep 17 00:00:00 2001 From: Venki Pallipadi Date: Fri, 9 May 2008 13:05:19 -0700 Subject: x86/PCI: X86_PAT & mprotect Some versions of X used the mprotect workaround to change caching type from UC to WB, so that it can then use mtrr to program WC for that region [1]. Change the mmap of pci space through /sys or /proc interfaces from UC to UC_MINUS. With this change, X will not need to use mprotect workaround to get WC type since the MTRR mapping type will be honored. The bug in mprotect that clobbers PAT bits is fixed in a follow on patch. So, this X workaround will stop working as well. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Suresh Siddha Signed-off-by: Ingo Molnar Signed-off-by: Jesse Barnes --- arch/x86/pci/i386.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c index 8af0f0bae2af..10fb308fded8 100644 --- a/arch/x86/pci/i386.c +++ b/arch/x86/pci/i386.c @@ -301,15 +301,13 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, prot = pgprot_val(vma->vm_page_prot); if (pat_wc_enabled && write_combine) prot |= _PAGE_CACHE_WC; - else if (pat_wc_enabled) + else if (pat_wc_enabled || boot_cpu_data.x86 > 3) /* * ioremap() and ioremap_nocache() defaults to UC MINUS for now. * To avoid attribute conflicts, request UC MINUS here * aswell. */ prot |= _PAGE_CACHE_UC_MINUS; - else if (boot_cpu_data.x86 > 3) - prot |= _PAGE_CACHE_UC; vma->vm_page_prot = __pgprot(prot); -- cgit v1.2.2