W dniu 12 sierpnia 2011 12:15 użytkownik David Woodhouse <[email protected]> napisał: > On some 64-bit DMA engines (my BCM4331, at least) with a ring buffer > that is not aligned to 8KiB, we often see bit 12 spuriously being set in > the B43_DMA64_RXSTATUS register. This will happen the first time the > ring fills and loops back to zero: > > [35755.186080] Read RXSTATUS 3f0 (makes offs 3f0, divided by 10 gives slot 3f > [35755.288366] Read RXSTATUS 1000 (makes offs 1000, divided by 10 gives slot > 100 > [35755.291007] ------------[ cut here ]------------ > [35755.291041] WARNING: at drivers/net/wireless/b43/dma.c:1700 > b43_dma_rx+0x5e/0x2df [b43]() > ... > [35766.745374] b43-phy41 debug: DMA RX: Dropping poisoned buffer. > > All we need to do is mask the offending bit out. The packets *are* where > they should be; it's just the high bit of the reported offset which is > weird. > > Signed-off-by: David Woodhouse <[email protected]> > > diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c > index 82168f8..92dd6d9 100644 > --- a/drivers/net/wireless/b43/dma.c > +++ b/drivers/net/wireless/b43/dma.c > @@ -247,6 +249,10 @@ static int op64_get_current_rxslot(struct b43_dmaring > *ring) > > val = b43_dma_read(ring, B43_DMA64_RXSTATUS); > val &= B43_DMA64_RXSTATDPTR; > + /* When the ring is not aligned to 8KiB, we sometimes get > + bit 12 (0x1000) set in the address. Mask it out; we > + only use a 4KiB ring. */ > + val &= B43_DMA_RINGMEMSIZE-1;
I still have to understand that B43_DMA_RINGMEMSIZE (it's equal to PAGE_SIZE, which is calculated in some magic way). However there should be spaces around minus. -- Rafał _______________________________________________ b43-dev mailing list [email protected] http://lists.infradead.org/mailman/listinfo/b43-dev
