Re: [Linux-ATM-General] [PATCH v2 1/1] solos-pci: Fix regression introduced by newest firmware

[chas w. - C. <ch...@cm...>]

i suspect gcc's memcmp can handle 4 bytes at a time after it gets to
proper alignment (which it already likely is given it is the
initial skb->data area) this also appears to be coming back from the
fpga on the card, so the author probably didnt have much choice in the
matter.

besides, you cant go fast enough for this matter on your dsl link
anyway :)

On Sun, 20 Mar 2011 19:19:07 -0700
Philip Prindeville <phi...@re...> wrote:

> I'm not especially worried about it...  Gcc has a lot of __builtin functions for memcpy, memcmp, strcmp, etc. and usually does a fairly efficient job of it...  I've not had to check lately, but I wouldn't be surprised if it even does a string unroll for short strings.  The test could be changed to:
> 
> if (state_str[0] != 'S' || strcmp(&state_str[1], "howtime"))
> 
> 
> and I wouldn't especially mind, but I did want to keep the amount of fingerprints down to a minimum.
> 
> Yes, I'm also old and grouchy... I remember having to write in BAL-360 and manage my own stack-frame... The PDP-11 was a breath of fresh air...
> 
> But anyway, like I said... wanted to keep patches to "low touch", especially since a lot of folks will be back-porting these fixes to 2.6.32 or even 2.6.27...
> 
> 
> On 3/20/11 7:11 PM, MIke Westall wrote:
> > I'll be the first to admit that (1) I'm a grouchy old guy who (2) first programmed on an IBM 1620 and then on a 360  Model 30 with 32K ram.  But why oh why do we need to use 9 byte string constants with per character compare to decide if the device is up or not :-(
> >
> >
> >
> >
> > Philip Prindeville wrote:
> >> The newest FPGA firmware on the Solos processors correctly signals carrier transitions, bitrate, etc.
> >>
> >> The driver previously ignored these messages, and the physical state was always ATM_PHY_SIG_UNKNOWN.
> >>
> >> Now that the board reports its state, we expose a bug whereby the transition from UNKNOWN to LOST causes us to release all VC's.
> >>
> >> We don't delete any VC's, but instead just send an indication of carrier change.
> >>
> >> Signed-off-by: Philip A Prindeville <ph...@re...>
> >> ---
> >>
> >> --- a/drivers/atm/solos-pci.c    2011-03-20 15:27:40.000000000 -0600
> >> +++ b/drivers/atm/solos-pci.c    2011-03-20 16:32:11.000000000 -0600
> >> @@ -382,8 +382,10 @@ static int process_status(struct solos_c
> >>
> >>       /* Anything but 'Showtime' is down */
> >>       if (strcmp(state_str, "Showtime")) {
> >>           atm_dev_signal_change(card->atmdev[port], ATM_PHY_SIG_LOST);
> >> +#if 0
> >>           atm_dev_release_vccs(card->atmdev[port]);
> >> +#endif
> >>           dev_info(&card->dev->dev, "Port %d: %s\n", port, state_str);
> >>         return 0;
> >>     }
> >>
> >>
> 
> 
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