Base Address Registers

NTDEV
1

Hi All,
I have a question regarding the BAR registers during the Hibernation time. This question is for all windows flavours[2000,XP,.net]. Also this is a SCSI miniport driver.

  1. When the Windows boots up say we have a value BAR-A for all the bar registers.
    2.Then I try to hibernate [or Crash Dump driver loads], here a fresh copy of the driver is loaded.

  2. Is it guaranteed that the BAR-A WILL not change.??

Simply put can BAR registers change when hibernation/crash dump driver loads??

I know that from miniport prespective this should not matter but I have a case where it might.

  • Thanks,
    Ajitabh

Yahoo! FareChase - Search multiple travel sites in one click.

2

You can’t assume BAR would not change. Theoretically, it could change on the
fly if PCI bus driver wants to do resource rebalancing. That’s why
IRP_MN_QUERY_STOP_DEVICE and IRP_MN_STOP_DEVICE exist on NT platform.

Calvin
Broadcom Corporation

From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Driver Coder
Sent: Wednesday, October 26, 2005 1:03 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Base Address Registers

Hi All,
??? I have a question regarding the BAR registers during the Hibernation
time. This question is for all windows flavours[2000,XP,.net]. Also this is a
SCSI miniport driver.
?
1.?When the Windows boots up say we have a value BAR-A for all the bar
registers.
2.Then I try to hibernate [or Crash Dump driver loads], here a fresh copy of
the driver is loaded.
?
3. Is it guaranteed that the BAR-A?WILL not change.??
?
Simply put can BAR registers change when hibernation/crash dump?driver
loads??
?
??? I know that from miniport prespective this should not matter but I have
a case where it might.
?

  • Thanks,
    Ajitabh

Yahoo! FareChase - Search multiple travel sites in one click. — Questions?
First check the Kernel Driver FAQ at
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ntdev as: xxxxx@broadcom.com To unsubscribe send a blank email to
xxxxx@lists.osr.com

3

Calvin (Hao) Guan wrote:

You can’t assume BAR would not change. Theoretically, it could change on the
fly if PCI bus driver wants to do resource rebalancing. That’s why
IRP_MN_QUERY_STOP_DEVICE and IRP_MN_STOP_DEVICE exist on NT platform.

But the important point here is that my BAR will not change unless my
device is stopped and restarted. Once I have been handed resources, I
can rely on them for the lifetime of this device instance. If my driver
is stopped as part of hibernation, then I my device might get a new BAR
when I reawaken. If I’m just told to go into a low-power state, that
can’t happen. Right?

–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.

4

Actually, this is false. If your device is in the started state at the time
that hibernation starts, and if your device has gotten a device usage
notification IRP saying that your on the hibernation path, then the PCI
driver will not change your BARs and it will not disable them as hibernation
begins.

–
Jake Oshins
Windows Kernel Group

This posting is provided “AS IS” with no warranties, and confers no rights.

“Calvin (Hao) Guan” wrote in message
news:xxxxx@ntdev…
You can’t assume BAR would not change. Theoretically, it could change on the
fly if PCI bus driver wants to do resource rebalancing. That’s why
IRP_MN_QUERY_STOP_DEVICE and IRP_MN_STOP_DEVICE exist on NT platform.

Calvin
Broadcom Corporation


From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Driver Coder
Sent: Wednesday, October 26, 2005 1:03 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Base Address Registers

Hi All,
I have a question regarding the BAR registers during the Hibernation
time. This question is for all windows flavours[2000,XP,.net]. Also this is
a
SCSI miniport driver.

1. When the Windows boots up say we have a value BAR-A for all the bar
registers.
2.Then I try to hibernate [or Crash Dump driver loads], here a fresh copy of
the driver is loaded.

3. Is it guaranteed that the BAR-A WILL not change.??

Simply put can BAR registers change when hibernation/crash dump driver
loads??

I know that from miniport prespective this should not matter but I have
a case where it might.

- Thanks,
Ajitabh

Yahoo! FareChase - Search multiple travel sites in one click. — Questions?
First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256 You are currently subscribed to
ntdev as: xxxxx@broadcom.com To unsubscribe send a blank email to
xxxxx@lists.osr.com