>From 56e4b14aa58612aeb41b51d73a75f85dd72127a1 Mon Sep 17 00:00:00 2001
From: Rene Herman <rene.herman@xxxxxxxxx>
Date: Sat, 31 May 2008 00:31:40 +0200
Subject: [PATCH] ISA: set 24-bit dma_mask for ISA devices.
dma_alloc_coherent() on x86 currently takes a passed in NULL device
pointer to mean that it should allocate an ISA compatible (24-bit)
buffer which is a bit of a hack.
The ALSA ISA drivers are the main consumers of this but have a struct
device in fact readily available.
For the legacy drivers, this sets the device dma_mask in preparation
for using the actual device with the DMA API so as to eventually not
need the NULL hack in dma_alloc_coherent().
This does not fix a current bug -- 2.6.26-rc1 stumbled over the NULL
hack in dma_alloc_coherent() but this has already been fixed in commit
4a367f3a9dbf2e7ffcee4702203479809236ee6e by Takashi Iwai.
Signed-off-by: Rene Herman <rene.herman@xxxxxxxxx>
Cc: Bjorn Helgaas <bjorn.helgaas@xxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
---
drivers/base/isa.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/base/isa.c b/drivers/base/isa.c
index d222239..efd5775 100644
--- a/drivers/base/isa.c
+++ b/drivers/base/isa.c
@@ -7,6 +7,7 @@
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
+#include <linux/dma-mapping.h>
#include <linux/isa.h>
static struct device isa_bus = {
@@ -141,6 +142,9 @@ int isa_register_driver(struct isa_driver *isa_driver, unsigned int ndev)
isa_dev->dev.release = isa_dev_release;
isa_dev->id = id;
+ isa_dev->dev.coherent_dma_mask = DMA_24BIT_MASK;
+ isa_dev->dev.dma_mask = &isa_dev->dev.coherent_dma_mask;
+
error = device_register(&isa_dev->dev);
if (error) {
put_device(&isa_dev->dev);
--
1.5.2.2
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