Hi Alan, Thursday, June 25, 2009, 11:05:42 AM, you wrote: > bmdma_setup is called at the start of the DMA command > bmdma_start is called to begin a DMA transfer > bmdma_stop is called to end one thank you for the hint. Maybe I misunderstand something, but this functions do not look like equivalents of old ide_dma_off, ide_dma_off_quietly and ide_dma_on commands. The logic implemented in the old code is "stop DMA transfer but do not disable DMA in case of errors". I've implemented UDMA support for EM8511 but cannot get MW-DMA working on EM8500. Either it is as slow as PIO mode or kernel complains about unhandled IRQ: platform: Probing driver pata_jasper with device pata_jasper JASPER PATA (IDE) chipset 8500: UDMA is not supported scsi0 : pata_jasper DEV: registering device: ID = 'host0' CLASS: registering class device: ID = 'host0' ata1: PATA max MWDMA2 irq 11 jasper_tune_chipset: slave = 0 speed = 0x08 jasper_tune_chipset: slave = 1 speed = 0x08 ata1.00: ATAPI: 9929D05E59V1.500P3311077, , max MWDMA2 jasper_tune_chipset: slave = 0 speed = 0x0c jasper_tune_chipset: slave = 0 speed = 0x22 ata1.00: configured for MWDMA2 DEV: registering device: ID = 'target0:0:0' scsi 0:0:0:0: CD-ROM 9929D05E 59V1.500P3311077 3311 PQ: 0 ANSI: 5 DEV: registering device: ID = '0:0:0:0' bus scsi: add device 0:0:0:0 scsi: Matched Device 0:0:0:0 with Driver sd scsi: Probing driver sd with device 0:0:0:0 scsi: Matched Device 0:0:0:0 with Driver sr scsi: Probing driver sr with device 0:0:0:0 irq 11: nobody cared (try booting with the "irqpoll" option) Function entered at [<011545e0>] from [<01046c98>] Function entered at [<01046c60>] from [<01046f24>] -- Best regards, Andrei mailto:andrei.martynov@xxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html