---------- Forwarded message ----------
From: Rupesh Kumar <[EMAIL PROTECTED]>
Date: Oct 10, 2006 1:37 PM
Subject: TD Hash table getting corrupted with Isochoronous transfers
To: [EMAIL PROTECTED]
Cc: linux-usb-users@lists.sourceforge.net, linux-usb-devel@lists.sourceforge.net


Hi All,

I  am working on embedded OHCI USB host controller on which i am using
 linux-2.6.14.

With Isochronous transfers after some time my board is getting hanged.
I observed that the TD Hash table is getting corrupted.

According to the OHCI Specification there is chance for 8 PSWs but in
the driver we are using only 2 PSW.but my hardware is always doing
8PSW DMA Transfer there by hardware is overwriting the Software fields
sitting immediately after the PSW.
struct td
{
       /* first fields are hardware-specified */
       __hc32          hwINFO;         /* transfer info bitmask */
       __hc32          hwCBP;          /* Current Buffer Pointer (or 0) */
       __hc32          hwNextTD;       /* Next TD Pointer */
       __hc32          hwBE;           /* Memory Buffer End Pointer */
       /* PSW is only for ISO.  Only 1 PSW entry is used, but on
        * big-endian PPC hardware that's the second entry.
        */
#define MAXPSW  2
       __hc16          hwPSW [MAXPSW];
       /* rest are purely for the driver's use */
       __u8            index;
       struct ed       *ed;
       struct td       *td_hash;       /* dma-->td hashtable */
       struct td       *next_dl_td;
       struct urb      *urb;
}

What is reason for giving only 2 PSW can we give extra 6 PSW to
overcome this issue.
Is it a hardware issue.

Regards
Kumar

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