# Re: weird speed difference with parallel port scanner

From: mh (moloch@nikocity.de)
Date: Fri Aug 11 2000 - 04:03:20 PDT

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  1.G. Jaeger, Fre, 11 Aug 2000 :
  > Hi Michael,
  >
  > I think this is a problem in the intercation with the drivers.
  > Check if the lp.o module is loaded prior to the pt_drv module.
  > Try and change the loading order:
  > First pt_drv, then lp.o.
  > I has been reported, that there are problems with connected
  > printers. but the speed problem is new to me.
  > I'll reactivate my old HP 500 color and check this next week...

  Hi Gerhard,
  I just recompiled the driver with debug enabled.
  The reason for this speed difference obviously is, that the
  port isn't detected as EPP if there's no printer connected to
  the scanner and therefore the SPP mode is used.
  I think this isn't a problem with the loading order of the modules,
  is this correct?
  (BTW if there is a printer, but switched off, you can't even load
  the pt_drv module)

  -------------------------------------------------
  2.G. Jaeger, Fre, 11 Aug 2000 :
  >I introduced this to the backend some weeks ago and encountered
  >sometimes the same effects. I think this behaviour should be fixed.
  >it makes me wonder that you are the first one to complain about this.
  >I'll fix it, okay?

  That' s of course okay. On the other hand, it isn't a bug. I just have no
  idea what's the purpose of this feature? Do other backends implement
  this too?
  At least this feature seems to confuse the frontends somehow, what makes
  scanning a little awkward.

  >The other thing, with the inexact sizes is IMO a problem of using
  >different metrics. The backend uses cm or mm, then it'll be converted
  >to inch and finally to pixels and motor steps...
  >I'm not sure how to fix this. If you have special settings with extreme
  >problems, let me know and I can try to workaround or even fix it.

  No, no, I didn' mean lossy transformations; the problems I had were all related
  to this magically changing scan area.

  Thanks a lot for your reply
  Michael

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