- /* lower transfer mode */
- if (ata_down_xfermask_limit(dev, 0) == 0)
- return ATA_EH_SOFTRESET;
+ /* lower transfer mode */
+ if (dev->spdn_cnt < 2) {
+ static const int dma_dnxfer_sel[] =
+ { ATA_DNXFER_DMA, ATA_DNXFER_40C };
+ static const int pio_dnxfer_sel[] =
+ { ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
+ int sel;
+
+ if (dev->xfer_shift != ATA_SHIFT_PIO)
+ sel = dma_dnxfer_sel[dev->spdn_cnt];
+ else
+ sel = pio_dnxfer_sel[dev->spdn_cnt];
+
+ dev->spdn_cnt++;
+
+ if (ata_down_xfermask_limit(dev, sel) == 0) {
+ action |= ATA_EH_SOFTRESET;
+ goto done;
+ }
+ }
+ }
+
+ /* Fall back to PIO? Slowing down to PIO is meaningless for
+ * SATA. Consider it only for PATA.
+ */
+ if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
+ (dev->ap->cbl != ATA_CBL_SATA) &&
+ (dev->xfer_shift != ATA_SHIFT_PIO)) {
+ if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
+ dev->spdn_cnt = 0;
+ action |= ATA_EH_SOFTRESET;
+ goto done;
+ }
+ }