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PNP: don't fail device init if no DMA channel available 

Most drivers for devices supporting ISA DMA can operate without DMA as well
(falling back zo PIO).  Thus it seems inappropriate for PNP to fail device
initialization in case none of the possible DMA channels are available.
Instead, it should be left to the driver to decide what to do if
request_dma() fails.

The patch at once adjusts the code to account for the fact that
pnp_assign_dma() now doesn't need to report failure anymore.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Adam Belay <ambx1@neo.rr.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Beulich 2007-10-16 23:31:07 -07:00 committed by Linus Torvalds
parent 36e02b6208
commit 7ef36390fa
1 changed files with 12 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/pnp/manager.c
View File

@ -161,7 +161,7 @@ static int pnp_assign_irq(struct pnp_dev *dev, struct pnp_irq *rule, int idx)
return 0; return 0;
} }
static int pnp_assign_dma(struct pnp_dev *dev, struct pnp_dma *rule, int idx) static void pnp_assign_dma(struct pnp_dev *dev, struct pnp_dma *rule, int idx)
{ {
resource_size_t *start, *end; resource_size_t *start, *end;
unsigned long *flags; unsigned long *flags;
@ -173,15 +173,14 @@ static int pnp_assign_dma(struct pnp_dev *dev, struct pnp_dma *rule, int idx)
}; };
if (idx >= PNP_MAX_DMA) { if (idx >= PNP_MAX_DMA) {
pnp_err pnp_err("More than 2 dmas is incompatible with pnp "
("More than 2 dmas is incompatible with pnp specifications."); "specifications.");
/* pretend we were successful so at least the manager won't try again */ return;
return 1;
} }
/* check if this resource has been manually set, if so skip */ /* check if this resource has been manually set, if so skip */
if (!(dev->res.dma_resource[idx].flags & IORESOURCE_AUTO)) if (!(dev->res.dma_resource[idx].flags & IORESOURCE_AUTO))
return 1; return;
start = &dev->res.dma_resource[idx].start; start = &dev->res.dma_resource[idx].start;
end = &dev->res.dma_resource[idx].end; end = &dev->res.dma_resource[idx].end;
@ -191,19 +190,17 @@ static int pnp_assign_dma(struct pnp_dev *dev, struct pnp_dma *rule, int idx)
*flags |= rule->flags | IORESOURCE_DMA; *flags |= rule->flags | IORESOURCE_DMA;
*flags &= ~IORESOURCE_UNSET; *flags &= ~IORESOURCE_UNSET;
if (!rule->map) {
*flags |= IORESOURCE_DISABLED;
return 1; /* skip disabled resource requests */
}
for (i = 0; i < 8; i++) { for (i = 0; i < 8; i++) {
if (rule->map & (1 << xtab[i])) { if (rule->map & (1 << xtab[i])) {
*start = *end = xtab[i]; *start = *end = xtab[i];
if (pnp_check_dma(dev, idx)) if (pnp_check_dma(dev, idx))
return 1; return;
} }
} }
return 0; #ifdef MAX_DMA_CHANNELS
*start = *end = MAX_DMA_CHANNELS;
#endif
*flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED;
} }
/** /**
@ -330,8 +327,7 @@ static int pnp_assign_resources(struct pnp_dev *dev, int depnum)
irq = irq->next; irq = irq->next;
} }
while (dma) { while (dma) {
if (!pnp_assign_dma(dev, dma, ndma)) pnp_assign_dma(dev, dma, ndma);
goto fail;
ndma++; ndma++;
dma = dma->next; dma = dma->next;
} }
@ -367,8 +363,7 @@ static int pnp_assign_resources(struct pnp_dev *dev, int depnum)
irq = irq->next; irq = irq->next;
} }
while (dma) { while (dma) {
if (!pnp_assign_dma(dev, dma, ndma)) pnp_assign_dma(dev, dma, ndma);
goto fail;
ndma++; ndma++;
dma = dma->next; dma = dma->next;
} }