From: "Jan Beulich" 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 Cc: Adam Belay Cc: Bjorn Helgaas Signed-off-by: Andrew Morton --- drivers/pnp/manager.c | 29 ++++++++++++----------------- 1 files changed, 12 insertions(+), 17 deletions(-) diff -puN drivers/pnp/manager.c~pnp-dont-fail-device-init-if-no-dma-channel drivers/pnp/manager.c --- a/drivers/pnp/manager.c~pnp-dont-fail-device-init-if-no-dma-channel +++ a/drivers/pnp/manager.c @@ -161,7 +161,7 @@ static int pnp_assign_irq(struct pnp_dev 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; unsigned long *flags; @@ -173,15 +173,14 @@ static int pnp_assign_dma(struct pnp_dev }; if (idx >= PNP_MAX_DMA) { - pnp_err - ("More than 2 dmas is incompatible with pnp specifications."); - /* pretend we were successful so at least the manager won't try again */ - return 1; + pnp_err("More than 2 dmas is incompatible with pnp " + "specifications."); + return; } /* check if this resource has been manually set, if so skip */ if (!(dev->res.dma_resource[idx].flags & IORESOURCE_AUTO)) - return 1; + return; start = &dev->res.dma_resource[idx].start; end = &dev->res.dma_resource[idx].end; @@ -191,19 +190,17 @@ static int pnp_assign_dma(struct pnp_dev *flags |= rule->flags | IORESOURCE_DMA; *flags &= ~IORESOURCE_UNSET; - if (!rule->map) { - *flags |= IORESOURCE_DISABLED; - return 1; /* skip disabled resource requests */ - } - for (i = 0; i < 8; i++) { if (rule->map & (1 << xtab[i])) { *start = *end = xtab[i]; 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 p irq = irq->next; } while (dma) { - if (!pnp_assign_dma(dev, dma, ndma)) - goto fail; + pnp_assign_dma(dev, dma, ndma); ndma++; dma = dma->next; } @@ -367,8 +363,7 @@ static int pnp_assign_resources(struct p irq = irq->next; } while (dma) { - if (!pnp_assign_dma(dev, dma, ndma)) - goto fail; + pnp_assign_dma(dev, dma, ndma); ndma++; dma = dma->next; } _