From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: Resend [PATCH 00/10] ARM: SMP initialization consolidation Date: Tue, 3 May 2011 15:57:42 +0200 Message-ID: <201105031557.42355.arnd@arndb.de> References: <1304129297-6614-1-git-send-email-robherring2@gmail.com> <4DBBA509.6080203@codeaurora.org> <20110502234012.GJ28001@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110502234012.GJ28001@n2100.arm.linux.org.uk> Sender: linux-sh-owner@vger.kernel.org To: linux-arm-kernel@lists.infradead.org Cc: Russell King - ARM Linux , Stephen Boyd , Linus Walleij , Srinidhi Kasagar , linux-arm-msm@vger.kernel.org, linux-sh@vger.kernel.org, Rob Herring , Paul Mundt , Daniel Walker , David Brown List-Id: linux-arm-msm@vger.kernel.org On Tuesday 03 May 2011, Russell King - ARM Linux wrote: > Such a SoC may wish to do things differently from the current approach > (which is basically bring up all cores at boot) particularly as the > performance gained from each CPU is far from identical. So I've been > nervous about moving the CPU map initialization into core code. > > Note that the low power CPU may not be the last in the set, so merely > limiting the system to two CPUs is not the answer. If I read the patches correctly, it's still strictly opt-in per platform. When a platform wants to support the setup you mentioned or something even stranger, all it would have to do is provide its own versions of the SMP pen and scu init function, right? Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Date: Tue, 03 May 2011 13:57:42 +0000 Subject: Re: Resend [PATCH 00/10] ARM: SMP initialization consolidation Message-Id: <201105031557.42355.arnd@arndb.de> List-Id: References: <1304129297-6614-1-git-send-email-robherring2@gmail.com> <4DBBA509.6080203@codeaurora.org> <20110502234012.GJ28001@n2100.arm.linux.org.uk> In-Reply-To: <20110502234012.GJ28001@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org On Tuesday 03 May 2011, Russell King - ARM Linux wrote: > Such a SoC may wish to do things differently from the current approach > (which is basically bring up all cores at boot) particularly as the > performance gained from each CPU is far from identical. So I've been > nervous about moving the CPU map initialization into core code. > > Note that the low power CPU may not be the last in the set, so merely > limiting the system to two CPUs is not the answer. If I read the patches correctly, it's still strictly opt-in per platform. When a platform wants to support the setup you mentioned or something even stranger, all it would have to do is provide its own versions of the SMP pen and scu init function, right? Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Tue, 3 May 2011 15:57:42 +0200 Subject: Resend [PATCH 00/10] ARM: SMP initialization consolidation In-Reply-To: <20110502234012.GJ28001@n2100.arm.linux.org.uk> References: <1304129297-6614-1-git-send-email-robherring2@gmail.com> <4DBBA509.6080203@codeaurora.org> <20110502234012.GJ28001@n2100.arm.linux.org.uk> Message-ID: <201105031557.42355.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tuesday 03 May 2011, Russell King - ARM Linux wrote: > Such a SoC may wish to do things differently from the current approach > (which is basically bring up all cores at boot) particularly as the > performance gained from each CPU is far from identical. So I've been > nervous about moving the CPU map initialization into core code. > > Note that the low power CPU may not be the last in the set, so merely > limiting the system to two CPUs is not the answer. If I read the patches correctly, it's still strictly opt-in per platform. When a platform wants to support the setup you mentioned or something even stranger, all it would have to do is provide its own versions of the SMP pen and scu init function, right? Arnd