Tejun Heo wrote: > Back in 2.6.17-rc2, a libata module parameter was added for atapi_dmadir. > > That's nice, but most SATA devices which need it will tell us about it > in their IDENTIFY PACKET response, as bit-15 of word-62 of the > returned data (as per ATA7, ATA8 specifications). > > So for those which specify it, we should automatically use the DMADIR bit. > Otherwise, disc writing will fail by default on many SATA-ATAPI drives. > > This patch adds ATA_DFLAG_DMADIR and make ata_dev_configure() set it > if atapi_dmadir is set or identify data indicates DMADIR is necessary. > atapi_xlat() is converted to check ATA_DFLAG_DMADIR before setting > DMADIR. > > Original patch is from Mark Lord. > > Signed-off-by: Tejun Heo <htejun@xxxxxxxxx> > Cc: Mark Lord <mlord@xxxxxxxxx> > --- > I don't have a bridge which sets DMADIR but so only checked atapi_dmadir > parameter. Thanks. > The patch looks good. However, it seems there is no realworld IDE-to-SATA bridge that requires DMADIR and also mangles IDENTIFY PACKET bit-15 of word-62 to indicate its presence. >From the previous test of the IDE-to-SATA bridges, only the Sil 3611 requires the host software to hint on ATAPI DMADIR. But Sil 3611 doesn't mangle IDENTIFY PACKET word-62: http://www.spinics.net/lists/linux-ide/msg01514.html Maybe we could use ata_dev_knobble() instead? i.e. If it's an ATAPI device && ata_dev_knobble() then we turn on DMADIR (regardless the bridge chip used since setting DMADIR won't hurt those don't need it.) -- albert - 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
