[PATCH] ide-cd: Handle strange interrupt on the Intel ESB2

The ESB2 appears to emit spurious DMA interrupts when configured for native
mode and handling ATAPI devices.  Stratus were able to pin this bug down and
produce a patch.  This is a rework which applies the fixup only to the ESB2
(for now).  We can apply it to other chips later if the same problem is found.

This code has been tested and confirmed to fix the problem on the tested
systems.

Signed-off-by: Alan Cox <alan@redhat.com>
(Most of the hard work done by Stratus however)
Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index 88214943d00ad776a0977507c4b5d721ed894949..5969cec58dc155c2f21aea7e72c4b6d6aca9eb94 100644 (file)
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -687,8 +687,15 @@ static void ide_dump_status_no_sense(ide_drive_t *drive, const char *msg, u8 sta
 static int cdrom_decode_status(ide_drive_t *drive, int good_stat, int *stat_ret)
 {
        struct request *rq = HWGROUP(drive)->rq;
+       ide_hwif_t *hwif = HWIF(drive);
        int stat, err, sense_key;
        
+       /* We may have bogus DMA interrupts in PIO state here */
+       if (HWIF(drive)->dma_status && hwif->atapi_irq_bogon) {
+               stat = hwif->INB(hwif->dma_status);
+               /* Should we force the bit as well ? */
+               hwif->OUTB(stat, hwif->dma_status);
+       }
        /* Check for errors. */
        stat = HWIF(drive)->INB(IDE_STATUS_REG);
        if (stat_ret)

diff --git a/drivers/ide/pci/piix.c b/drivers/ide/pci/piix.c
index cdc3aab9ebcbc46676c76f6e5569f13eb214505a..b1e9a8eba6b679697d9cbe6fb7e6aa38158fbcbc 100644 (file)
--- a/drivers/ide/pci/piix.c
+++ b/drivers/ide/pci/piix.c
@@ -505,6 +505,10 @@ static void __devinit init_hwif_piix(ide_hwif_t *hwif)
                /* This is a painful system best to let it self tune for now */
                return;
        }
+       /* ESB2 appears to generate spurious DMA interrupts in PIO mode
+          when in native mode */
+       if (hwif->pci_dev->device == PCI_DEVICE_ID_INTEL_ESB2_18)
+               hwif->atapi_irq_bogon = 1;
 
        hwif->autodma = 0;
        hwif->tuneproc = &piix_tune_drive;

diff --git a/include/linux/ide.h b/include/linux/ide.h
index 9c2050293f17c81727d70ffc44eea24a95e7e9f1..64e070f62a872bbf22cc376bfe9ef51d6499a4ac 100644 (file)
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -796,6 +796,7 @@ typedef struct hwif_s {
        unsigned        sg_mapped  : 1; /* sg_table and sg_nents are ready */
        unsigned        no_io_32bit : 1; /* 1 = can not do 32-bit IO ops */
        unsigned        err_stops_fifo : 1; /* 1=data FIFO is cleared by an error */
+       unsigned        atapi_irq_bogon : 1; /* Generates spurious DMA interrupts in PIO mode */
 
        struct device   gendev;
        struct completion gendev_rel_comp; /* To deal with device release() */