On Mon, Mar 13, 2006 at 05:13:36AM -0500, Jeff Garzik wrote: > Tejun Heo wrote: > >On Mon, Mar 13, 2006 at 04:52:28AM -0500, Jeff Garzik wrote: > > > >>Tejun Heo wrote: > >> > >>>On Mon, Mar 13, 2006 at 03:29:24AM -0500, Jeff Garzik wrote: > >>> > >>> > >>>>Tejun Heo wrote: > >>>> > >>>> > >>>>>Add per-dev pio/mwdma/udma_mask. All transfer mode limits used to be > >>>>>applied to ap->*_mask which unnecessarily restricted other devices > >>>>>sharing the port. This change will also benefit later EH speed down > >>>>>and hotplug. > >>>>> > >>>>>Signed-off-by: Tejun Heo <htejun@xxxxxxxxx> > >>>> > >>>>I don't see much value in the separation. Rather than 3 separate > >>>>masks, it seems like this patch would be simplified if you simply added > >>>>dev->xfer_mask. > >>>> > >>> > >>> > >>>The thing is that ap->*_mask's are separated the same way and all > >>>masking constants are defined as such. e.g. > >>> > >>> ap->udma_mask &= ATA_UDMA5; > >>>or > >>> ap->udma_mask &= ATA_UDMA_MASK_40C; > >>> > >>>Making dev->*_mask's the same enables share those constants and code > >>>convention. So, things to consider here are... > >>> > >>>1. Port xfer masks are defined as three separate masks. > >>> > >>>2. All the constants are defined according to that. > >>> > >>>3. Three separate masks are easier to deal with for LLDD's. > >> > >>Separate masks is better for the LLDD interface, but the packed version > >>seems superior for internal libata use. > > > > > >Yeah, dev->*_mask's will be used by LLDD's. Actually, in patch #4 of > >this series, sata_sil's ->dev_config() does exactly that. Also, mode > >mask filtering can be done by diddling dev->*_mask's. > > > > > >>No reason why ATA_UDMA_MASK_40C can't simply operate on a packed > >>xfer_mask variable, for example. > > > > > >Because it's used to filter ap->*_mask and to allow LLDD's use the > >same constants on dev->*_mask's. > > > >Do you think LLDD's shouldn't access dev->*_mask's? > > When I spoke of "LLDD API", I largely meant the pio_mask/etc. in > ata_port_info. That's the easiest way to present such information to > driver maintainers. > > OTOH, at runtime ->dev_config() and friends should probably just > manipulate dev->xfer_mask. I see. So, ata_port_info uses pio/mwdma/udma_mask and ata_port and ata_device use single xfer_mask and all the masking constants are converted to mask single xfer_mask. Sounds good to you? -- tejun - : 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
