Messages in this thread | | | Date | Wed, 26 Feb 2003 16:37:34 +0100 (MET) | From | Geert Uytterhoeven <> | Subject | Re: [PATCH] fixed pcnet32 multicast listen on big endian |
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On Wed, 26 Feb 2003, Jeff Garzik wrote: > Geert Uytterhoeven wrote: > > On Sun, 23 Feb 2003, Geert Uytterhoeven wrote: > >>On Wed, 5 Feb 2003, Marcus Meissner wrote: > >>>This fixes multicast listen for pcnet32 on at least powerpc and powerpc64 > >>>kernels. > >>> > >>>The mcast_table is in memory referenced by the card and so it needs > >>>to be accessed in little endian mode. > >>> > >>>Ciao, Marcus > >>> > >>>--- linux-2.4.19/drivers/net/pcnet32.c.be 2003-02-05 07:59:27.000000000 +0100 > >>>+++ linux-2.4.19/drivers/net/pcnet32.c 2003-02-05 08:00:22.000000000 +0100 > >>>@@ -1534,7 +1534,9 @@ > >>> > >>> crc = ether_crc_le(6, addrs); > >>> crc = crc >> 26; > >>>- mcast_table [crc >> 4] |= 1 << (crc & 0xf); > >>>+ mcast_table [crc >> 4] = le16_to_cpu( > >> > >> ^^^^^^^^^^^ > >> > >>>+ le16_to_cpu(mcast_table [crc >> 4]) | (1 << (crc & 0xf)) > >>>+ ); > >> > >>Shouldn't the first conversion be `cpu_to_le16'? > > > > > > Ugh, a quick grep shows that this driver _always_ uses `le*_to_cpu()' to > > convert from CPU to little endian. > > Cosmetically you are correct, and I prefer it to be changed eventually. > > However programatically, it has no effect, because those cpu_to_foo and > foo_to_cpu functions either swap, or they don't. Direction doesn't > matter terribly much :)
That's true.
BTW, you save one swap by changing the code to
mcast_table [crc >> 4] |= cpu_to_le16(1 << (crc & 0xf));
Because the order of bitwise or and swap doesn't matter.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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