[617] in linux-scsi channel archive
Changes in 1.3.26
daemon@ATHENA.MIT.EDU (Eric Youngdale)
Wed Sep 13 22:39:40 1995
From: "Eric Youngdale" <eric@aib.com>
Date: Wed, 13 Sep 1995 20:08:54 -0400
In-Reply-To: "Eric Schenk" <schenk@cs.toronto.edu>
"AHA152x driver broken in 1.3.x" (Sep 4, 6:14pm)
To: linux-scsi@vger.rutgers.edu
There are a number of interesting changes in 1.3.26.
First of all, I added support for select() in scsi_generics. There
are applications where this could be handy, and it was easy to do.
Secondly, I have fixed some bugs involving rereading of partition
tables when the media is changed.
Finally, I checked in my patches to provide better support for bus
resets. The way it works is that the mid-level scsi code uses some
heuristics to determine how badly things are wedged. This flag is in the
Scsi_Host structure and is intended to be just a suggestion to the low-level
reset function as to how it should proceed. The low level reset() function
is free to ignore this if it wishes, but if the low-level reset function
performs a bus reset, it should or in the SCSI_RESET_BUS_RESET bit into
the return code.
The return code tells the mid-level code what to expect. If there
is a bus reset, we mark each device on the bus as having been reset, so that
we know what to do if we get a UNIT_ATTENTION/CHECK_CONDITION coming back.
Unfortunately a few patches of mine got lost before I sent them to Linus
(I just realized this now) - those patches will convert a UA/CC into
an automatic retry for devices on a bus that has been reset. The reason
for this is that this code is normally passed up to the upper level drivers,
and sometimes is considered an error. I will make the appropriate changes
and send them off to Linus.
I added code to the 1542 driver to follow the recommendation of
the mid-level code. This is very hard for me to test, so I don't know if
it actually does any good or not - I would be very interested in hearing
any results from people. The idea is that we should be able to recover
from
situations that we previously got stuck under. Under no circumstances
should things be worse than they were before.
-Eric
--
"The woods are lovely, dark and deep. But I have promises to keep,
And lines to code before I sleep, And lines to code before I sleep."
