Re: [linux-usb-devel] question on flushing buffers and spinning down disk
Alan Stern <[email protected]>
| Newsgroups | gmane.linux.scsi,gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On Fri, 28 Sep 2007, Oliver Neukum wrote: > Am Donnerstag 27 September 2007 schrieb Alan Stern: > > Have you thought about how autoresume would fit into this picture? I > > don't think you can rely on usb-storage telling the SCSI core to resume > > devices when it gets handed a command, because the commands to spin-up > > the drives would have to be transmitted first. (The sample patch you I had another look at your patch. It calls scsi_device_quiesce(), which causes all normal requests to be deferred. Hence under normal operation the device would never autoresume -- user requests would be deferred and never sent to usb-storage. It will be necessary to modify scsi_prep_fn(), so that if the device is in the SDEV_QUIESCE state because of autosuspend when a request arrives, a workqueue routine initiates an autoresume. Alan Stern - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html