Hello, On Mon, May 20, 2013 at 12:51:20PM +0200, Vincent Pelletier wrote: > Putting the knob on the port is just a way I thought about to hold the > configuration before the drive is plugged into the system (because so far I > was focussed on host-side being hot-pluggable, I indeed didn't consider the > opposite situation) so it can be used before libata tries to access the > device. Right, we don't even have the sysfs node before probing. I forgot about that. > So it would be something like: > - plug device (or boot up) > -> detection times out, device "half" configured (sysfs node present, drive > not usable) > - cd $DEVICE_IN_SYSFS > - echo 1 > atapi_dmadir > - echo 1 > (rescan|reinit|...) > > If it's ok, I'll write a patch to add a rescan write-only file (will also be > independent from the 2 other patches). Ugh... so, this is inherently racy between the probing code and admin. Maybe we should just implement a new libata.force param and forget about dynamic configuration? One more thing. In the ata_exec_internal_sg(), DMADIR should be set iff DMA is being used, right? So, it should also check tf->protocol. It prolly should test tf->protocol == ATAPI_PROT_DMA instead of cdb. Thanks. -- tejun -- 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
