Each try takes about ~3300 ticks of a timer (got this info by some
inserts of u32 cur = timer_read(); dprintf(1, "tries %d=%d\n", tries,
cur);). A bit unsure how it translates to seconds (the CPU frequency
of my laptop fluctuates between 1.4GHz and 2.5GHz), so I did some
stopwatch tests and can't notice anything. It's an extra ~0.3 seconds
delay if I plug this USB drive at all, but no delay difference between
a normal and "write protect" mode (only in "write protect" it behaves
erroneously).
I've looked through a lot of logs and this USB in a "write protect"
mode always works on a 2nd try, even if I insert "msleep(5000);"
before the 1st try, so I guess it's a try based. As this code is only
for blockcmd, I'm not getting any extra delay if i.e. a DVD disc isn't
present in a DVD drive. And to be honest I haven't encountered any
cases where a 3rd try was needed, I put one more just in case and to
make my fix more universal.
On Wed, Dec 9, 2020 at 8:36 PM Kevin O'Connor <ke...@koconnor.net> wrote:
>
> On Thu, Dec 03, 2020 at 07:06:59AM +0300, Mike Banon wrote:
> > At least some USB drives with a write protect switch (e.g. Netac U335)
> > could report "MEDIUM NOT PRESENT" for a while if a write protection is
> > enabled. Instead of stopping the initialization attempts immediately,
> > stop only after getting this report for 3 times, to ensure the
> > successful initialization of such a "broken hardware".
>
> Thanks. In general it seems fine to me. I do have a couple of questions.
>
> How long does this add to the total boot time? Some users are
> particularly sensitive to total boot time, and the "MEDIUM NOT
> PRESENT" check is specifically there to reduce total boot time. If we
> retry that check it may be a regression for some users.
>
> Does the troublesome device just require 3 retries, or is it time
> based (that is, does it just require additional time to detect there
> is something present, or is there something special about the third
> request)?
>
> -Kevin
>
>
> >
> > Signed-off-by: Mike Banon <mikeb...@gmail.com>
> >
> > diff --git a/src/hw/blockcmd.c b/src/hw/blockcmd.c
> > index 1f15081..6b6fea9 100644
> > --- a/src/hw/blockcmd.c
> > +++ b/src/hw/blockcmd.c
> > @@ -144,8 +144,9 @@ scsi_is_ready(struct disk_op_s *op)
> > dprintf(6, "scsi_is_ready (drive=%p)\n", op->drive_fl);
> >
> > /* Retry TEST UNIT READY for 5 seconds unless MEDIUM NOT PRESENT is
> > - * reported by the device. If the device reports "IN PROGRESS",
> > + * reported by the device 3 times. If the device reports "IN
> > PROGRESS",
> > * 30 seconds is added. */
> > + int tries = 3;
> > int in_progress = 0;
> > u32 end = timer_calc(5000);
> > for (;;) {
> > @@ -167,8 +168,11 @@ scsi_is_ready(struct disk_op_s *op)
> >
> > // Sense succeeded.
> > if (sense.asc == 0x3a) { /* MEDIUM NOT PRESENT */
> > - dprintf(1, "Device reports MEDIUM NOT PRESENT\n");
> > - return -1;
> > + tries--;
> > + dprintf(1, "Device reports MEDIUM NOT PRESENT - %d tries
> > left\n",
> > + tries);
> > + if (!tries)
> > + return -1;
> > }
> >
> > if (sense.asc == 0x04 && sense.ascq == 0x01 && !in_progress) {
> > _______________________________________________
> > SeaBIOS mailing list -- seabios@seabios.org
> > To unsubscribe send an email to seabios-le...@seabios.org
_______________________________________________
SeaBIOS mailing list -- seabios@seabios.org
To unsubscribe send an email to seabios-le...@seabios.org
