From: Owen Smith <owen.smith@citrix.com>
Date: Tue, 26 Jun 2018 11:17:32 +0000 (+0100)
Subject: Relax check for new bindings
X-Git-Tag: 9.0.0-rc1~60
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=4bfef97168df986ac302f6892ed8c38f81c0b432;p=pvdrivers%2Fwin%2Fxenbus.git

Relax check for new bindings

Only if the major version part of the revision changes is it unsafe to
update the drivers without removing the unplug keys (thereby forcing a
fallback to emulated devices on the next reboot). Minor version changes
should be backwards compatible (within a reasonable time-frame).

Signed-off-by: Owen Smith <owen.smith@citrix.com>

Edited commit comment.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
---

diff --git a/src/coinst/coinst.c b/src/coinst/coinst.c
index f19d108..fa899f3 100644
--- a/src/coinst/coinst.c
+++ b/src/coinst/coinst.c
@@ -999,6 +999,7 @@ SupportDeviceID(
     unsigned int    Revision;
     int             Count;
     DWORD           Index;
+    DWORD           LatestRevision;
     HRESULT         Error;
 
     DeviceID = strrchr(DeviceID, '&');
@@ -1022,9 +1023,10 @@ SupportDeviceID(
     goto fail2;
 
 found:
-    // If we don't match the latest revision then it means the driver
-    // binding will change.
-    if (Index < ARRAYSIZE(DeviceRevision) - 1)
+    // If major part of the child device's revision does not match the major
+    // part of the latest revision then it means the driver binding will change.
+    LatestRevision = DeviceRevision[ARRAYSIZE(DeviceRevision) - 1];
+    if ((Revision & 0xFF000000) != (LatestRevision & 0xFF000000))
         *NewBinding = TRUE;
 
     Log("%x", Revision);