Messages in this thread | | | Date | Thu, 16 May 2002 14:25:26 -0400 (EDT) | From | "Richard B. Johnson" <> | Subject | Re: [PATCH] #2 VIA Rhine stalls: TxAbort handling |
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On Thu, 16 May 2002, 'Roger Luethi' wrote:
> On Thu, 16 May 2002 18:03:25 +0800, Shing Chuang wrote: > > As following three error conditions occurred, the VT6102 & VT86C100A > > chip are designed to shutdown TX for driver to examine the error frame. > > > > 1. Tx fifo underrun. > > > > 2. Tx Abort (Too many collisions occurred). > > > > 3. TxDescriptors status write back error. (Only on VT6102 chip) > > Hey, thanks! That's exactly the piece of information I've been looking for. > > > All the three conditions caused the TXON bit of CR1 went off. the > > driver must wait a little while until the bit go off, reset the pointer of > > [...] > > do {} while (BYTE_REG_BITS_IS_ON(CR0_TXON,&pMacRegs->byCR0)); > > The driver "waits a little" in the interrupt handler? How long can that > take, worst case?
Forever..........^;)
> I don't know of many places where the kernel stops to > wait for an external device to change some value. >
Yep... should never wait inside an ISR, to say nothing about the potential wait-forever.
Even if the chip never breaks, you end up with reports like.. "Strange, I make frisbees when buring CDs while M$ machines do backups over the network..."
Or, I can't play ".wav" files anymore unless I unplug from the network...
Stuff has to play together. Sometimes this means you can't get the maximum-theoretical-possible through-put from your connected devices.
The worse-case driver is where the programmer decided to turn interrupts back on in the ISR.... to let higher-priority interrupts occur... FYI, there are always higher-priority interrupts that will take the CPU away... you lose big-time.
Cheers, Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
Windows-2000/Professional isn't.
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