On 4/21/06, Anita Tailor <tailor.anita@xxxxxxxxx> wrote: > > > > On 20/04/06, Mandeep Sandhu <mandeep.stinger@xxxxxxxxx> wrote: > > On 4/18/06, Greg KH <greg@xxxxxxxxx> wrote: > > > On Tue, Apr 18, 2006 at 11:22:50AM +0530, Mandeep Sandhu wrote: > > > > On 4/18/06, Greg KH < greg@xxxxxxxxx> wrote: > > > > > On Tue, Apr 18, 2006 at 10:26:05AM +0530, Mandeep Sandhu wrote: > > > > > > Hi all, > > > > > > > > > > > > How does one control the behavior of the LED's present on the > various usb > > > > > > flash drives. Is it controlled solely by software or is it like > that > > > > > > the usb host controller > > > > > > controls the LED's operation. eg: when I write to my flash drive > the > > > > > > the LED blinks. > > > > > > Is this done via some usb driver or does the usb host controller > does > > > > > > that for us > > > > > > when we issue a write command to the drive? Is usbled.c under > drivers/usb/misc > > > > > > responsible for controlling this operation? Any pointers are > welcome. > > > > > > > > > > No, there is no way to control it, it's up to the device itself. > > > > > > > > Well, Greg, the reason I was asking was because I wanted to know if > the LED > > > > of my drive could be switched off when I umount it. In windows I > noticed that > > > > the LED is switched off when the drive is ready to be unplugged. Is it > that they > > > > might be removing power to the drive? Could we acheive a similar > result? > > > > > > Yes, Windows is removing power to that specific port. > > > > > > And yes, we can also do that if you want (unloading the whole USB host > > > controller driver is overkill and not recommended, as it will prevent > > > any other USB device from working in your machine.) > > > > > > See the archives of the linux-usb-devel and linux-pm mailing lists for a > > > pointer to a program that lets you turn off the power for some USB hub > > > ports (note that it will not work on all hardware.) > > > > > Just one more question...before I go on my "hunt for the RED OKTOBER(LED)" > :) > > > > Does "unmounting" mean the device can no longer be used? because it > > makes sense to > > turn off the LED only then...to indicate that the system no longer > > recognizes this device. > > > > Or is that we still do some raw I/O from/to it? Then I think switching > > off the LED is not > > the right thing to do. > > > > > good luck, > > > > thanks. I'll need loads fo it! > > > > > I think sending start/stop (1Bh) SCSI command to the flash drive turn > off the LED if it's handling is present in the firmware of the flash drive . > I tried this and it is working with my flash drive. > > There is a section on the LED page in Hut1_11.pdf (available on > www.usb.org). > I think these commands can used to control behavior of LED's present on > device . > Thanks Anita. I'll look at the docs to see if the commands are vendor dependent. The device that I have is a SanDisk (Cruizer mini). -mandeep > -Anita > > > > > > > > > > > -- > > Kernelnewbies: Help each other learn about the Linux kernel. > > Archive: http://mail.nl.linux.org/kernelnewbies/ > > FAQ: http://kernelnewbies.org/faq/ > > > > > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
