Messages in this thread | | | Date | Fri, 22 Aug 2008 09:40:00 +0200 | From | Nicolas Ferre <> | Subject | Re: [patch 2.6.27-rc3] at91_mci: don't use coherent dma buffers |
| |
Pierre, Andrew,
You can add my...
David Brownell : > From: David Brownell <dbrownell@users.sourceforge.net> > > At91_mci is abusing dma_free_coherent(), which may not be called > with IRQs disabled. I saw "mkfs.ext3" on an MMC card objecting > voluminously as each write completed: > > WARNING: at arch/arm/mm/consistent.c:368 dma_free_coherent+0x2c/0x224() > [<c002726c>] (dump_stack+0x0/0x14) from [<c00387d4>] (warn_on_slowpath+0x4c/0x68) > [<c0038788>] (warn_on_slowpath+0x0/0x68) from [<c0028768>] (dma_free_coherent+0x2c/0x224) > r6:00008008 r5:ffc06000 r4:00000000 > [<c002873c>] (dma_free_coherent+0x0/0x224) from [<c01918ac>] (at91_mci_irq+0x374/0x420) > [<c0191538>] (at91_mci_irq+0x0/0x420) from [<c0065d9c>] (handle_IRQ_event+0x2c/0x6c) > ... > > This bug has been around for a LONG time. The MM warning is > from late 2005, but the driver merged a year later ... so I'm > puzzled why nobody noticed this before now. > > The fix involves noting that this buffer shouldn't be DMA-coherent; > it's just used for normal DMA writes. So replace it with standard > kmalloc() buffering and DMA mapping calls. > > This is the quickie fix. A better one would not rely on allocating > large bounce buffers. (Note that dma_alloc_coherent could have failed > too, but that case was ignored... kmalloc is a bit more likely to > fail though.) > > Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
...
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
-- Nicolas Ferre
| |