diff -Nur linux-2.6.32.orig/drivers/ata/libata-scsi.c linux-2.6.32/drivers/ata/libata-scsi.c --- linux-2.6.32.orig/drivers/ata/libata-scsi.c 2009-12-03 14:51:21.000000000 +1100 +++ linux-2.6.32/drivers/ata/libata-scsi.c 2011-01-22 20:28:16.432525503 +1100 @@ -1099,13 +1099,13 @@ /* configure max sectors */ blk_queue_max_sectors(sdev->request_queue, dev->max_sectors); + sdev->sector_size = ATA_SECT_SIZE; + if (dev->class == ATA_DEV_ATAPI) { struct request_queue *q = sdev->request_queue; void *buf; - /* set the min alignment and padding */ - blk_queue_update_dma_alignment(sdev->request_queue, - ATA_DMA_PAD_SZ - 1); + /* set DMA padding */ blk_queue_update_dma_pad(sdev->request_queue, ATA_DMA_PAD_SZ - 1); @@ -1119,12 +1119,24 @@ blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN); } else { - /* ATA devices must be sector aligned */ - blk_queue_update_dma_alignment(sdev->request_queue, - ATA_SECT_SIZE - 1); sdev->manage_start_stop = 1; } + /* + * ata_pio_sectors() expects buffer for each sector to not cross + * page boundary. Enforce it by requiring buffers to be sector + * aligned, which works iff sector_size is not larger than + * PAGE_SIZE. ATAPI devices also need the alignment as + * IDENTIFY_PACKET is executed as ATA_PROT_PIO. + */ + if (sdev->sector_size > PAGE_SIZE) + ata_dev_printk(dev, KERN_WARNING, + "sector_size=%u > PAGE_SIZE, PIO may malfunction\n", + sdev->sector_size); + + blk_queue_update_dma_alignment(sdev->request_queue, + sdev->sector_size - 1); + if (dev->flags & ATA_DFLAG_AN) set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);