[Qemu-devel] [PATCH] RTL8139 rx-path fixes

[Qemu-devel] [PATCH] RTL8139 rx-path fixes

[Tim Deegan]

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Two small changes: fix the buffer wraparound code for 64k ring-buffers,
and enable (and fix) the crc32 checksum calculation.  These changes are
needed for the the Realtek driver that shipped with 32-bit Vista.

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@xensource.com>, XenSource UK Limited
Registered office c/o EC2Y 5EB, UK; company number 05334508

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Index: hw/rtl8139.c
===================================================================
RCS file: /sources/qemu/qemu/hw/rtl8139.c,v
retrieving revision 1.10
diff -u -r1.10 rtl8139.c
--- hw/rtl8139.c	11 Jul 2007 22:48:58 -0000	1.10
+++ hw/rtl8139.c	17 Jul 2007 10:09:03 -0000
@@ -53,9 +53,8 @@
 /* debug RTL8139 card C+ mode only */
 //#define DEBUG_RTL8139CP 1
 
-/* RTL8139 provides frame CRC with received packet, this feature seems to be
-   ignored by most drivers, disabled by default */
-//#define RTL8139_CALCULATE_RXCRC 1
+/* Calculate CRCs properly on Rx packets */
+#define RTL8139_CALCULATE_RXCRC 1
 
 /* Uncomment to enable on-board timer interrupts */
 //#define RTL8139_ONBOARD_TIMER 1
@@ -747,7 +746,7 @@
         int wrapped = MOD2(s->RxBufAddr + size, s->RxBufferSize);
 
         /* write packet data */
-        if (wrapped && s->RxBufferSize < 65536 && !rtl8139_RxWrap(s))
+        if (wrapped && !(s->RxBufferSize < 65536 && rtl8139_RxWrap(s)))
         {
             DEBUG_PRINT((">>> RTL8139: rx packet wrapped in buffer at %d\n", size-wrapped));
 
@@ -1023,7 +1022,7 @@
 
         /* write checksum */
 #if defined (RTL8139_CALCULATE_RXCRC)
-        val = cpu_to_le32(crc32(~0, buf, size));
+        val = cpu_to_le32(crc32(0, buf, size));
 #else
         val = 0;
 #endif
@@ -1129,7 +1128,7 @@
 
         /* write checksum */
 #if defined (RTL8139_CALCULATE_RXCRC)
-        val = cpu_to_le32(crc32(~0, buf, size));
+        val = cpu_to_le32(crc32(0, buf, size));
 #else
         val = 0;
 #endif

Re: [Qemu-devel] [PATCH] RTL8139 rx-path fixes

[Igor Kovalenko]

On 7/17/07, Tim Deegan <Tim.Deegan@xensource.com> wrote:
> Two small changes: fix the buffer wraparound code for 64k ring-buffers,
> and enable (and fix) the crc32 checksum calculation.  These changes are
> needed for the the Realtek driver that shipped with 32-bit Vista.
>

Fix for crc32 first argument may be needed for smc91c111.c and
mcf_fec.c as well, if I understand correctly, zlib documentation
indeed states that pre- and post-conditioning (one's complement) is
performed within crc32 function.

-- 
Kind regards,
Igor V. Kovalenko