From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 19 Jun 2004 16:16:02 +0200 To: Alan Stern Cc: Benjamin Herrenschmidt , Sven Luther , Alan Cox , Nicolas DET , Linux-USB , linuxppc-dev list Subject: Re: [linux-usb-devel] [Patch] for UHCI driver (from kernel 2.6.6). Message-ID: <20040619141602.GD18025@pegasos> References: <1087595028.2061.295.camel@gaston> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: From: Sven Luther Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Sat, Jun 19, 2004 at 09:59:53AM -0400, Alan Stern wrote: > On Fri, 18 Jun 2004, Benjamin Herrenschmidt wrote: > > > > I recently changed a few mb() calls to wmb(), because they only protected > > > data the CPU was writing to be read by the device. Do you think changing > > > all the wmb()'s back to mb()'s would make a difference? > > > > > > (Actually it seems likely that this is _not_ directly related to the > > > original problem, but it might be important anyway.) > > > > Well, the problem on ppc is that the eieio done by wmb() (or implicitely > > done by all writeX IO accessors) will only order stores in the same > > domain. That is cacheable aren't ordered vs. non cacheables. > > I'm not familiar with the term "eieio"; can you explain it? Enforced In-Order Execution of I/O. Page 8-61 of the Programing Environments for 32-Bit Microprocessors, by motorola, well, at least on my version. Friendly, Sven Luther ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/