On 02/27/2017 09:42 AM, John Kasunich wrote: > > On Sun, Feb 26, 2017, at 03:51 PM, Jon Elson wrote: >> Actually, I thought option 1 was the "best", but required a >> bit more code and more testing. >> Since I've discovered the offending line occurs in ONE and >> only one place in the whole driver (I think), >> then conditional compilation of one copy of the source seems >> like a workable solution. > Option 1 seems complex, and you really don't want to be twiddling parport > bits on every LinuxCNC startup, who knows what is connected to those bits. Well, the driver certainly twiddles some bits as it scans the bus to see what PPMC devices are out there. If you don't have one of the Pico Systems boards attached, you'd have no reason to invoke the ppmc driver. I'm not contemplating touching the generic parport driver, only hal_ppmc. > I prefer option 2. If there are tweaks needed to help the driver adapt to > the hardware, the logical thing to do is to tell the driver about those > tweaks at load time. Yes, this may actually be easier, as it doesn't require major mucking around in the Makefiles to produce two versions of hal_ppmc. I'm now leaning more toward this. I think I will make the default setting to be the "new way", so existing configs won't have to be changed to use it. > I'm not a big fan of option 3, but I suppose it works. But imagine if you > later find another idiosyncrasy that requires the driver to do some other > thing differently? Do you make "hal_ppmc", and "hal_ppmc_old" and > "hal_ppmc_not_so_old"? > > Better to have command line args with meaningful names like "change_dir=1" > for the old behavior, and "change_dir=0" for the new behavior. The default > should be the old behavior, and the manual page should say to try the > alternate if the default doesn't work. OK, I'll think about your parameter name, and unless I come up with a better one, that will be it. No, I don't want the default to be the old behavior, as that has been PROVEN to break on at least a couple parport chips. I am not, at present, able to find any parport chip that fails with the new method. (Still digging in boxes for some older PCI cards to try.)
Thanks much, John! Jon ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
