On 2012年03月29日 15:06, Rajasekhar Pulluru wrote: > Hi, > > While registering for an interrupt handler, we could specify > IRQF_DISABLED flag to request_irq() to disable all other interrupts > while the handler's execution, except the one that's being registered. > I understand that this flag's usage is reserved only for > performance-sensitive interrupts that needs to execute quickly and > setting this for general (non-performance sensitive cases) use is > considered bad. > > Qn.1: Is this the fast way of interrupt handling? Does this flag > distinguish between fast and slow interrupts? > > Arm supports several processor modes that includes FIQ and Interrupt > request mode. FIQ has higher priority over normal interrupt mode. > > Qn.2: Is FIQ mode supported by ARM is equivalent to doing > IRQF_DISABLED in hardware? What is/are the significance/advantages of > FIQ mode? > From software side: ARM FIQ implementation COPY FIQ handler right at FIQ vector, however IRQ implementation needs to interrogate interrupt controller to find which interrupt fired. From hardware side: FIQ save less registers than IRQ, also has higher priority than IRQ. > Thanks& Regards, > Rajasekhar > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > -- Love each day! --bill _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
