On Mon, Jan 3, 2011 at 11:42 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Mon, 3 Jan 2011, Tejun Heo wrote: > >> > Runtime suspend should not occur unless all the child devices (i.e., >> > the attached drives) are already suspended. This means it is not >> > necessary to synchronize any operations, since there shouldn't be any >> > other accesses to the hardware going on. Therefore there is no need to >> > use the error handler. >> >> Well, it's not that simple I'm afraid. EH actions are asynchronous. >> Even if all the downstream devices are suspended, PHY events can >> happen any time and EH could be active. Hmmm... a delta but it would >> make more sense to put only the controller into hot sleep while >> leaving the disk alone for rotating devices. > > That could be done. How do you tell whether a particular drive is > rotational? > I don't think there is a kernel flag for it (yet). Per ATA-8 there is flag in the identify block. http://markmail.org/message/2vonazw4bck7nefa As that email says, I don't know how reliable the flag is. Greg -- 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
