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    SubjectRe: 2.6.26-rc1 regression: ISA DMA broken (bisected)
    Date
    On Wednesday 14 May 2008 12:41:56 pm Rene Herman wrote:
    > On 14-05-08 17:40, Rene Herman wrote:
    >
    > CC list trimmed as now PNP and ALSA specific.
    >
    > > Like this? With this (on top of the previous patch setting the
    > > dma_mask ofcourse) legacy ISA actually appears to be fine but it's
    > > then ISAPnP which goes bonkers again. Sigh. Getting an allocation
    > > failure. Don't understand why yet since pnp_alloc_dev() definitely
    > > sets the mask already. Will stare...
    >
    > You're in a maze of struct device *s, all alike... I was passing the
    > pnp_card->dev instead of the initialized pnp_dev->dev.
    >
    > And, not doing so brings out a difference between ISAPnP and legacy ISA
    > again insofar that legacy ISA does not consist of cards with multiple
    > devices. We just have the single struct device * for the ISA device.
    >
    > This therefore would be the easiest solution (and works fine) but seems
    > a bit of a hack. Bjorn, do you have an opinion? If I abstract things out
    > a bit more I might be able to do this nicer. One might on the other hand
    > argue that the dma_mask is going to be constant for all card devices so
    > might as well just use the card dev.

    I agree, it seems a bit of a hack to use a DMA mask from the card
    instead of from the device, since the driver should be programming
    the device to do the DMA.

    But I know very little about pnp_card in general, so don't attach too
    much weight to my opinion.

    > sound/{isa,oss} together with drivers/isdn/hisax/ are the only pnp_card
    > users.
    >
    > diff --git a/drivers/pnp/card.c b/drivers/pnp/card.c
    > index a762a41..a2842a7 100644
    > --- a/drivers/pnp/card.c
    > +++ b/drivers/pnp/card.c
    > @@ -7,6 +7,7 @@
    > #include <linux/module.h>
    > #include <linux/ctype.h>
    > #include <linux/slab.h>
    > +#include <linux/dma-mapping.h>
    > #include <linux/pnp.h>
    > #include "base.h"
    >
    > @@ -167,6 +168,9 @@ struct pnp_card *pnp_alloc_card(struct pnp_protocol *protocol, int id, char *pnp
    > sprintf(card->dev.bus_id, "%02x:%02x", card->protocol->number,
    > card->number);
    >
    > + card->dev.coherent_dma_mask = DMA_24BIT_MASK;
    > + card->dev.dma_mask = &card->dev.coherent_dma_mask;
    > +
    > dev_id = pnp_add_card_id(card, pnpid);
    > if (!dev_id) {
    > kfree(card);
    >
    >




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