Connecting USB 2.0 Hard disk that goes to STANDBY

mmreddy54 · 08-13-2009, 05:09 AM

Hello All,

I have just joined this group. We are developing a Set-Top-Box based on Sigma chipset SMP8654, GNU/Linux Kernel version 2.6.12.

When we connect USB 2.0 Seagate Hard disk (connected to the STB) goes to STANDBY mode the OS is suppose to bring the drive back to active as soon as any read/write call is issued. But, some how drive is not becoming active and USB port is becoming un-usable till hard reboot.

Can some one please help me out!

Thanks

Mohan Reddy

Mara · 08-13-2009, 02:01 PM

Welcome to LQ!
Moderator note: I have moved your post to Linux-Hardware, where it seems to fit better.

Are you sure USB is still working in the standby? The thing is that if you enter too much sleep mode, the USB effectively disconnects. It maybe your case. I would read the disk's documentation and make sure that 1) the standby keeps USB running 2) the kernel doesn't enter such a power save mode that the processor powers USB down. You can start from checking if you have the right voltage when it's in standby.

mmreddy54 · 08-14-2009, 09:56 AM

Before mounting/accessing the device, if you check the device status using TEST UNIT READY command and if it is in STANDBY mode then bring the device to ACTIVE by using START STOP UNIT command. One can find the SCSI Primary/Multimedia commands in sg3_utils. (Ref Docs: INCITS-T10/1731-D, T10/1836D).

With this work-around problem is solved.

Thanks

Mohan Reddy