From mboxrd@z Thu Jan 1 00:00:00 1970 To: David Edelsohn Cc: Richard Henderson , Paul.Mackerras@cs.anu.edu.au, linuxppc-dev@lists.linuxppc.org, linux-fbdev@vuser.vu.union.edu Subject: Re: [linux-fbdev] Re: readl() and friends and eieio on PPC References: <9908120516.AA43198@marc.watson.ibm.com> From: Jes Sorensen Date: 12 Aug 1999 09:32:33 +0200 In-Reply-To: David Edelsohn's message of "Thu, 12 Aug 1999 01:16:14 -0400" Message-ID: Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: >>>>> "David" == David Edelsohn writes: >>>>> Richard Henderson writes: Richard> But it isn't zero cost. It's not high cost, but that's not Richard> the same thing. David> Is your assumption that you want to provide the infrastructure David> to write high-performance device drivers or to write device David> drivers that don't require as much expertise and knowledge to David> produce correct results? There are conflicting goals in this David> design providing different benefits to Linux. I am certainly up for high performance device drivers. Even having writel do the syncing there are enough other pitfalls for people to take into account. Some of these are much harder to understand than dealing with write ordering and as such, trying to make things invisible are only giving us a false guarantee. Ie. if we want to use spin locks in the kernel we need to teach people how to use them correctly. Jes [[ This message was sent via the linuxppc-dev mailing list. Replies are ]] [[ not forced back to the list, so be sure to Cc linuxppc-dev if your ]] [[ reply is of general interest. Please check http://lists.linuxppc.org/ ]] [[ and http://www.linuxppc.org/ for useful information before posting. ]]