From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp3.clb.oleane.net (smtp3.clb.oleane.net [213.56.31.19]) by ozlabs.org (Postfix) with ESMTP id 0A166682F4 for ; Wed, 28 Sep 2005 03:34:19 +1000 (EST) From: =?iso-8859-1?Q?G=E9rard_Gu=E9vel?= To: "'Andy Fleming'" Date: Tue, 27 Sep 2005 19:36:53 +0200 Message-ID: <000a01c5c38a$0f77cda0$5201a8c0@GEG2400> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" In-Reply-To: <5D83ECE9-90F7-4BE2-B173-C20CB868E9F6@freescale.com> Cc: linuxppc-embedded@ozlabs.org Subject: RE: How to use SPE on MPC8541 List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > You say the application runs, right? So what made you check the SPE > bit state? The kernel keeps SPE disabled by default so it doesn't > have to save the upper 32 bits of the registers every context > switch. When a process uses SPE for the first time, an exception is > triggered, the kernel enables SPE for that process, and then that > process should be able to use SPE every time it gets cpu time. > > How are you determining that the SPE bit is not set? Is your > application not executing the SPE instructions? > > Andy Yes the application runs. I wrote a mini driver with an ioctl which performs a mfmsr() call and returns the value to the user application. I called this ioctl at several times before and after executing SPE code. I already tried to manually force the SPE bit with another ioctl which performs a enable_kernel_spe() call. The bit SPE is right set at this time but disappears later. I don't know if using ioctls is a right way to check the bit. Any idea ? Thanks Gérard