Am Mittwoch, 14. Mai 2003 04:28 schrieben Sie: > Sorry about the dud post earlier. > > Hi, > I have some issues with accessing IO ports in the driver I am > writing... > > First I do a pci_enable_device(...), then pci_request_regions(...), > and finally ioremap(...). IMHO, you try to get iomem, not ioport ;-) > > ioremap always returns a null pointer. It seems that it needs to be > used for memory mapped IO only... The documentation with the kernel > seems to imply that it needs to be always used (for portability). > IO using [in|out][b|w|l] seems to work, ie doesn't crash but does not > return correct results either. > Whereas [read|write][b|w|l] will cause a segfault (due to the null > pointer). > > Can someone please point me to the proper way of doing this (I have > not found any sample code where this appears to work). > > tom. code examples are available at the kernel source (i.e. the framebuffer drivers in /usr/src/linux/drivers/video aty128fb.c tridentfb.c). also see Rubini's book for linux device drivers which is available for online reading. HTH, Franz
