From 2b9f99eae28cddb7b15ca48bc4ee76d646063274 Mon Sep 17 00:00:00 2001 From: Frank Mori Hess Date: Sat, 9 Jun 2001 20:07:57 +0000 Subject: [PATCH] fixed race between conversions and fifo overflow check --- comedi/drivers/das800.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/comedi/drivers/das800.c b/comedi/drivers/das800.c index 424122c2..f8b075a9 100644 --- a/comedi/drivers/das800.c +++ b/comedi/drivers/das800.c @@ -345,12 +345,13 @@ static void das800_interrupt(int irq, void *d, struct pt_regs *regs) return; } - /* read 16 bits from dev->iobase and dev->iobase + 1 */ - dataPoint = inb(dev->iobase + DAS800_LSB); - dataPoint += inb(dev->iobase + DAS800_MSB) << 8; /* loop while card's fifo is not empty (and make sure loop terminates by limiting to 256 iterations) */ - for(i = 0; (dataPoint & FIFO_EMPTY) == 0 && i < max_loops; i++) + for(i = 0; i < max_loops; i++) { + /* read 16 bits from dev->iobase and dev->iobase + 1 */ + dataPoint = inb(dev->iobase + DAS800_LSB); + dataPoint += inb(dev->iobase + DAS800_MSB) << 8; + if(dataPoint & FIFO_EMPTY) break; if( dataPoint & FIFO_OVF ) { comedi_spin_unlock_irqrestore(&dev->spinlock, irq_flags); @@ -380,23 +381,12 @@ static void das800_interrupt(int irq, void *d, struct pt_regs *regs) async->buf_int_ptr += sizeof(sampl_t); if(devpriv->count > 0) devpriv->count--; } - /* read 16 bits from dev->iobase and dev->iobase + 1 */ - dataPoint = inb(dev->iobase + DAS800_LSB); - dataPoint += inb(dev->iobase + DAS800_MSB) << 8; } /* we can release spinlock now since we dont case if hardware conversions are enabled anymore */ comedi_spin_unlock_irqrestore(&dev->spinlock, irq_flags); if(i == max_loops) comedi_error(dev, "possible problem with loop in interrupt handler"); - /* check for overflow on last data point */ - if( dataPoint & FIFO_OVF ) - { - comedi_error(dev, "DAS800 FIFO overflow"); - das800_cancel(dev, dev->subdevices + 0); - comedi_error_done(dev, s); - return; - } comedi_bufcheck(dev,s); if(devpriv->count > 0 || devpriv->forever == 1) { @@ -408,6 +398,17 @@ static void das800_interrupt(int irq, void *d, struct pt_regs *regs) /* otherwise, stop taking data */ } else { + /* read 16 bits from dev->iobase and dev->iobase + 1 */ + dataPoint = inb(dev->iobase + DAS800_LSB); + dataPoint += inb(dev->iobase + DAS800_MSB) << 8; + /* check for overflow on last data point */ + if( dataPoint & FIFO_OVF ) + { + comedi_error(dev, "DAS800 FIFO overflow"); + das800_cancel(dev, dev->subdevices + 0); + comedi_error_done(dev, s); + return; + } disable_das800(dev); /* diable hardware triggered conversions */ comedi_done(dev, s); } -- 2.26.2