Re: Calibration issues with USB disc present.

From: George Anzinger (george_at_mvista.com)
Date: 11/14/05

  • Next message: Dave Jones: "Re: [PATCH] oops-tracing: mention digital photos" 
    Date:	Mon, 14 Nov 2005 13:52:12 -0800
To: john stultz <johnstul@us.ibm.com>

    john stultz wrote:
    > On Mon, 2005-11-14 at 10:49 -0800, Greg KH wrote:
    >
    >>On Mon, Nov 14, 2005 at 10:56:05AM -0800, George Anzinger wrote:
    >>
    >>>Greg KH wrote:
    >>>
    >>>>On Sat, Nov 12, 2005 at 08:06:37AM -0800, George Anzinger wrote:
    >>>>
    >>>>>Greg KH wrote:
    >>>>
    >>>>On these boxes, I'd just recommend disabling USB legacy support
    >>>>completly, if possible. And then complain loudly to the vendor to fix
    >>>>their BIOS.
    >>>
    >>>But if one is booting from that device...
    >>
    >>Booting from a USB device? I can see this happening when installing a
    >>distro, and you boot from the USB cdrom, but not for "normal"
    >>operations.

    I think it was a hard drive they were trying to support.
    >>
    >>Oh well, publicly mock the manufacturer for doing horrible things in
    >>their BIOS and then no one will buy the boxes, and we will not have
    >>problems :)

    Long term, maybe, but it will not close the bug report I have in hand...
    >
    >
    > I suspect the right fix is in-between. We should try to push hardware
    > makers away from using SMIs recklessly, but we should also do our best
    > to work around those that don't. The same problems crop up w/
    > virtualization where time-based calibration may be interrupted.
    >
    > George, again, there has been some SMI resistant delay calibration code
    > added recently. You mentioned this problem was seen on 2.4 kernel, so
    > you could verify that the new code in 2.6.14 works and if so, try
    > backporting it.
    >
    > If not we need to see what else we can do about improving delay
    > calibration (its a similar tick-based problem to what I'm addressing
    > with the timeofday rework) or reducing the use of delay by using
    > something else.
    >
    I will look at that code, but we also need to address the same problem in the TSC calibration area. 

    -- 
George Anzinger   george@mvista.com
HRT (High-res-timers):  http://sourceforge.net/projects/high-res-timers/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
  • Next message: Dave Jones: "Re: [PATCH] oops-tracing: mention digital photos"

    Relevant Pages

    • Re: Calibration issues with USB disc present.
      ... George, again, there has been some SMI resistant delay calibration code ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: Design of a programmable delay line
      ... I can do recalibration in the video blanking time (this for a video ... should stay between 3 and 4 ns for the whole temperature range, ... so you can assume that there are enough calibration cycles. ... For a future project I need to design a programmable delay line. ...
      (comp.arch.fpga)
    • RE: IO-APIC problem with 2.6.14-rt9
      ... >based delay ... traces show that the new calibration code results in a bogomips ... >TSC based and with my code we use the loop based delay (since the TSC ...
      (Linux-Kernel)
    • Re: The BogoMIPS value sometimes too low on Intel Mobile P3
      ... > which take into consideration SMIs occuring during the calibration ... > loop. ... The BogoMIPS value is now very "stable", i.e. not changing greatly from boot ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • touch screen driver --working?
      ... I have a query here regarding how does a touch screen driver work? ... When I launch an qt application, the touch on edit dropdown ... How do I set these calibration points & what is their importance? ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)