[SCSI] megaraid_{mm,mbox}: 64-bit DMA capability checker

This patch contains
- a fix for 64-bit DMA capability check in megaraid_{mm,mbox} driver.
- includes changes (going back to 32-bit DMA mask if 64-bit DMA mask
failes) suggested by James with previous patch.
- addition of SATA 150-4/6 as commented by Vasily Averin.

With patch, the driver access PCIconfiguration space with dedicated
offset to read a signature. If the signature read, it means that the
controller has capability to handle 64-bit DMA.
Without this patch, the driver used to blindly claim 64-bit DMA
capability.
The issue has been reported by Vasily Averin [vvs@sw.ru].
Thank you Vasily for the reporting.

Signed-Off By: Seokmann Ju <seokmann.ju@lsil.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/Documentation/scsi/ChangeLog.megaraid b/Documentation/scsi/ChangeLog.megaraid
index c173806c91fa..fd8939e0045d 100644
--- a/Documentation/scsi/ChangeLog.megaraid
+++ b/Documentation/scsi/ChangeLog.megaraid
@@ -1,3 +1,64 @@
+Release Date    : Fri May 19 09:31:45 EST 2006 - Seokmann Ju <sju@lsil.com>
+Current Version : 2.20.4.9 (scsi module), 2.20.2.6 (cmm module)
+Older Version   : 2.20.4.8 (scsi module), 2.20.2.6 (cmm module)
+
+1.      Fixed a bug in megaraid_init_mbox().
+        Customer reported "garbage in file on x86_64 platform".
+        Root Cause: the driver registered controllers as 64-bit DMA capable
+        for those which are not support it.
+        Fix: Made change in the function inserting identification machanism
+        identifying 64-bit DMA capable controllers.
+
+        > -----Original Message-----
+        > From: Vasily Averin [mailto:vvs@sw.ru]
+        > Sent: Thursday, May 04, 2006 2:49 PM
+        > To: linux-scsi@vger.kernel.org; Kolli, Neela; Mukker, Atul;
+        > Ju, Seokmann; Bagalkote, Sreenivas;
+        > James.Bottomley@SteelEye.com; devel@openvz.org
+        > Subject: megaraid_mbox: garbage in file
+        >
+        > Hello all,
+        >
+        > I've investigated customers claim on the unstable work of
+        > their node and found a
+        > strange effect: reading from some files leads to the
+        >  "attempt to access beyond end of device" messages.
+        >
+        > I've checked filesystem, memory on the node, motherboard BIOS
+        > version, but it
+        > does not help and issue still has been reproduced by simple
+        > file reading.
+        >
+        > Reproducer is simple:
+        >
+        > echo 0xffffffff >/proc/sys/dev/scsi/logging_level ;
+        > cat /vz/private/101/root/etc/ld.so.cache >/tmp/ttt  ;
+        > echo 0 >/proc/sys/dev/scsi/logging
+        >
+        > It leads to the following messages in dmesg
+        >
+        > sd_init_command: disk=sda, block=871769260, count=26
+        > sda : block=871769260
+        > sda : reading 26/26 512 byte blocks.
+        > scsi_add_timer: scmd: f79ed980, time: 7500, (c02b1420)
+        > sd 0:1:0:0: send 0xf79ed980                  sd 0:1:0:0:
+        >         command: Read (10): 28 00 33 f6 24 ac 00 00 1a 00
+        > buffer = 0xf7cfb540, bufflen = 13312, done = 0xc0366b40,
+        > queuecommand 0xc0344010
+        > leaving scsi_dispatch_cmnd()
+        > scsi_delete_timer: scmd: f79ed980, rtn: 1
+        > sd 0:1:0:0: done 0xf79ed980 SUCCESS        0 sd 0:1:0:0:
+        >         command: Read (10): 28 00 33 f6 24 ac 00 00 1a 00
+        > scsi host busy 1 failed 0
+        > sd 0:1:0:0: Notifying upper driver of completion (result 0)
+        > sd_rw_intr: sda: res=0x0
+        > 26 sectors total, 13312 bytes done.
+        > use_sg is 4
+        > attempt to access beyond end of device
+        > sda6: rw=0, want=1044134458, limit=951401367
+        > Buffer I/O error on device sda6, logical block 522067228
+        > attempt to access beyond end of device
+
 Release Date    : Mon Apr 11 12:27:22 EST 2006 - Seokmann Ju <sju@lsil.com>
 Current Version : 2.20.4.8 (scsi module), 2.20.2.6 (cmm module)
 Older Version   : 2.20.4.7 (scsi module), 2.20.2.6 (cmm module)