Search Linux Wireless

Re: [PATCH] Clarify pci_iomap() usage for MMIO-only devices

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Linus Torvalds wrote:
The old situation with SATA drivers that had

	if (iomem)
		writel(..)
	else
		outl(..)

in the cases that needed it (and used hardcoded writel/outl in the cases that didn't) was an example of code that "in theory" is faster. But dammit, in practice that mattered not one whit, and what iomap() tries to do is to attack the _real_ problem we had in that area.
Which had nothing what-so-ever to do with any branches.

And none of those issues are a factor at all in ath5k (which spawned this sub-discussion), or indeed many other drivers. The above code you cite is -generic-, hardware agnostic code.

Most new hardware is MMIO-only, making ioread32() only for drivers that care about legacy IO support, something that is being slowly phased out. e.g. legacy IDE, legacy 10/100 mbps ethernet NICs with the dual MMIO/PIO register spaces.

	Jeff



-
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Host AP]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Linux Kernel]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Device Mapper]
  Powered by Linux