From: Thomas Gleixner > Sent: 14 May 2021 14:02 > > David, > > On Thu, May 13 2021 at 10:36, David Laight wrote: > > >> -----Original Message----- > >> From: Maximilian Luz <luzmaximilian@xxxxxxxxx> > > can you please fix your mail client and spare us the useless header > duplication in the reply? I have to delete them by hand - must have forgotten, I can't fix outlook :-) > > It is also worth noting that the probe code is spectacularly crap. > > It writes 0xff and then checks that 0xff is read back. > > Almost anything (including a failed PCIe read to the ISA bridge) > > will return 0xff and make the test pass. > > unsigned char probe_val = ~(1 << PIC_CASCADE_IR); > > outb(probe_val, PIC_MASTER_IMR); > new_val = inb(PIC_MASTER_IMR); > > How is that writing 0xFF? Sorry I misread the code and diagnostic output. In any case writing a value and expecting the same value back isn't exactly a high-quality probe. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
