1 files changed, 23 insertions, 16 deletions

diff --git a/drivers/ide/pci/piix.c b/drivers/ide/pci/piix.c
index a909684ee61b..56feb939f82a 100644
--- a/drivers/ide/pci/piix.c
+++ b/drivers/ide/pci/piix.c
@@ -215,17 +215,26 @@ static unsigned int init_chipset_ich(struct pci_dev *dev)
 }
 
 /**
- *      piix_dma_clear_irq      -       clear BMDMA status
- *      @drive: IDE drive to clear
+ *      ich_clear_irq   -       clear BMDMA status
+ *      @drive: IDE drive
  *
- *      Called from ide_intr() for PIO interrupts
- *      to clear BMDMA status as needed by ICHx
+ *      ICHx contollers set DMA INTR no matter DMA or PIO.
+ *      BMDMA status might need to be cleared even for
+ *      PIO interrupts to prevent spurious/lost IRQ.
  */
-static void piix_dma_clear_irq(ide_drive_t *drive)
+static void ich_clear_irq(ide_drive_t *drive)
 {
         ide_hwif_t *hwif = HWIF(drive);
         u8 dma_stat;
 
+        /*
+         * ide_dma_end() needs BMDMA status for error checking.
+         * So, skip clearing BMDMA status here and leave it
+         * to ide_dma_end() if this is DMA interrupt.
+         */
+        if (drive->waiting_for_dma || hwif->dma_base == 0)
+                return;
+
         /* clear the INTR & ERROR bits */
         dma_stat = inb(hwif->dma_base + ATA_DMA_STATUS);
         /* Should we force the bit as well ? */
@@ -293,21 +302,19 @@ static void __devinit init_hwif_piix(ide_hwif_t *hwif)
                 hwif->ultra_mask = hwif->mwdma_mask = hwif->swdma_mask = 0;
 }
 
-static void __devinit init_hwif_ich(ide_hwif_t *hwif)
-{
-        init_hwif_piix(hwif);
-
-        /* ICHx need to clear the BMDMA status for all interrupts */
-        if (hwif->dma_base)
-                hwif->ide_dma_clear_irq = &piix_dma_clear_irq;
-}
-
 static const struct ide_port_ops piix_port_ops = {
         .set_pio_mode           = piix_set_pio_mode,
         .set_dma_mode           = piix_set_dma_mode,
         .cable_detect           = piix_cable_detect,
 };
 
+static const struct ide_port_ops ich_port_ops = {
+        .set_pio_mode           = piix_set_pio_mode,
+        .set_dma_mode           = piix_set_dma_mode,
+        .clear_irq              = ich_clear_irq,
+        .cable_detect           = piix_cable_detect,
+};
+
 #ifndef CONFIG_IA64
  #define IDE_HFLAGS_PIIX IDE_HFLAG_LEGACY_IRQS
 #else
@@ -331,9 +338,9 @@ static const struct ide_port_ops piix_port_ops = {
         { \
                 .name           = DRV_NAME, \
                 .init_chipset   = init_chipset_ich, \
-                .init_hwif      = init_hwif_ich, \
+                .init_hwif      = init_hwif_piix, \
                 .enablebits     = {{0x41,0x80,0x80}, {0x43,0x80,0x80}}, \
-                .port_ops       = &piix_port_ops, \
+                .port_ops       = &ich_port_ops, \
                 .host_flags     = IDE_HFLAGS_PIIX, \
                 .pio_mask       = ATA_PIO4, \
                 .swdma_mask     = ATA_SWDMA2_ONLY, \