I rebuilt kernel with 2.4.20 with patch , then I can not set the DMA mode on my hda drive. > hdparm -d 1 /dev/hda /dev/hda: setting using_dma to 1(on) HDIO_SET_DMA failed: Operation not permitted using_dma = 0 (off) I have no problem with old REDHAT7.1. >From my .config, CONFIG_BLK_DEV_IDEDMA_PCI = y # CONFIG_BLK_DEV_IDEDMA_FORCED CONFIG_IDEDMA_PCI_AUTO = y CONFIG_BLK_IDEDMA = y Any comment or suggestion? Bo - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html