On 2014-07-07 21:37, loody wrote:
hi Bryn:
2014-07-07 17:20 GMT+08:00 Bryn M. Reeves <bmr@xxxxxxxxxx>:
On Sun, Jul 06, 2014 at 01:18:03AM +0800, loody wrote:
hi all:
we met a USB Hard Disk that will go to suspend if host stop
sending scsi command over 5mins.
To save the IO, kernel will keep the file in page cache as much as
he can and under this circumstances, the scsi command may disappear
for a while longer enough to cause the device suspend.
is there any kernel config or module parameter can do the dummy
read or scsi command periodically?
No but you could set up a simple cron job to call an sg3_utils command.
E.g. issue an sg_read for one sector to the device every 4m:
*/4 * * * * sg_read count=1 if=/dev/<disk>
Since my target platform arm embedded system,
does that mean I should include sg_read in my Busybox
or
cross-compile sg_read from sg3_utils?
appreciate your kind help,
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sgread is not included in BusyBox but you should have "touch".
Create a dummy file on the disk and let cron touch it every 4 minutes.
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