On Sat, Mar 14, 2015 at 03:58:39PM +0100, Marc Kleine-Budde wrote: > On 03/14/2015 03:38 PM, Ahmed S. Darwish wrote: > >> Applied to can. This will go into David's net tree and finally into > >> net-next. Then I'll apply patches 2+3. Nag me, if I forget about them ;) > >> > > > > Thanks! :-) > > > > So if I've understood correctly, this patch will go to -rc5 and > > the rest will go into net-next? > > > > If so, IMHO patch #2 should also go to -rc5. I know it's usually > > frowned up on to add further patches at this late -rc stage, but > > here's my logic: > > > > The original driver code just _arbitrarily_ assumed a MAX_TX_URB > > value of 16 parallel transmissions. This value was chosen, it seems, > > because the driver was heavily based on esd_usb2.c and the esd code > > just did so :-( > > > > Meanwhile, in the Kvaser hardware at hand, if I've increased the > > driver's max parallel transmissions little above the recommended > > limit reported by firmware, the firmware breaks up badly, reports a > > massive list of internal errors, and the candump traces becomes > > sort of an internal mess hardly related to the actual frames sent > > and received. > > In this particular hardware, what's the limit as reported by the firmware? >
48 max oustanding tx, which is quite big in itself it seems. Other drivers in the tree range between 10 (Peak) and 20 tx (8dev). > > In my case, I was lucky that the brand we own here (*) had a higher > > max outstanding transmissions value than 16. But if there is hardware > > Okay - higher. > > > out there with a max oustanding tx support < 16 (#), such hardware > > will break badly under a heavy transmission load :-( > > I see. > > If you add this motivation to the patch description and let the subject > reflect that this is a "fix" or safety measure rather than a possible > performance improvement, no-one will say anything against this patch :D > True; I admit the "fix" part should've been clearer :-) Will send a better worded commit message then. Thanks a lot, Darwish -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
