From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mbox1.netikka.net ([213.250.81.202]:46990 "EHLO mbox1.netikka.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752401Ab0BNSon (ORCPT ); Sun, 14 Feb 2010 13:44:43 -0500 Message-ID: <4B784498.8030509@mandriva.org> Date: Sun, 14 Feb 2010 20:44:40 +0200 From: Thomas Backlund MIME-Version: 1.0 To: Larry Finger CC: "linux-wireless@vger.kernel.org" , "netdev@vger.kernel.org" Subject: Re: linux-2..6.33-rc7 and b43 References: <4B77C819.9050602@mandriva.org> <4B782670.9080001@lwfinger.net> In-Reply-To: <4B782670.9080001@lwfinger.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: Larry Finger skrev 14.2.2010 18:36: > On 02/14/2010 03:53 AM, Thomas Backlund wrote: >> Hi, >> (please cc me on replies) >> >> We have a user that tried out b43, but got this in the logs: >> >> --- cut --- >> 65858:Feb 9 22:05:16 elmo kernel: b43-phy2 ERROR: This device does not >> support DMA on your system. Please use PIO instead. 65859:Feb 9 >> 22:05:16 elmo kernel: b43-phy2 ERROR: CONFIG_B43_FORCE_PIO must >> be set in your kernel configuration. >> 65860:Feb 9 22:05:16 elmo kernel: b43-phy2 debug: Adding Interface type 2 >> 65861:Feb 9 22:05:16 elmo kernel: b43-phy2 ERROR: Fatal DMA error: >> 0x00000400, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000 >> >> 65862:Feb 9 22:05:16 elmo kernel: b43-phy2 ERROR: This device does not >> support DMA on your system. Please use PIO instead. >> 65863:Feb 9 22:05:16 elmo kernel: b43-phy2 ERROR: CONFIG_B43_FORCE_PIO >> must be set in your kernel configuration. >> --- cut --- >> >> >> >> But reading the Kconfig help, it states: >> --- cut --- >> config B43_FORCE_PIO >> bool "Force usage of PIO instead of DMA" >> depends on B43&& B43_DEBUG >> ---help--- >> This will disable DMA and always enable PIO instead. >> >> Say N! >> This is only for debugging the PIO engine code. You do >> _NOT_ want to enable this. >> --- cut --- >> >> >> So, >> wich one is it ? >> >> Do I belive the dmesg output, or the Kconfig ? >> >> Note, >> the b43 works for the user if he enable the CONFIG_B43_FORCE_PIO. >> >> But I'm thinking of this problem from a distro point of view. >> Will it break for others if I enable it ? > >> From a distro point of view, you would not want to set FORCE_PIO as the > performance penalty would be very large. > As I suspected. Thanks for confirming it. > You do not give the specific details on the problem system; however, it is > probably a BCM4312 802.11 b/g device with PCI ID 14e4:4315 being used with an > Atom processor in a netbook. We have no fix. > Sorry about the missing info... I asked a few times from the user, and got no reponse until today a few hours after your response... It is indeed a BCM4312 802.11 b/g device with PCI ID 14e4:4315 on a Dell laptop with a Intel ICH9M series chipset and a Intel Core(TM)2 Duo CPU T7250 @ 2.00GHz. > In the 2.6.34 code, b43 will be changed to allow the selection of PIO mode at > run time rather than compile time. For a distro, this method is clearly > superior. Those users that need PIO can select it without forcing the > performance penalty on everyone. The patch was too late for the 2.6.33 merge, > and too intrusive to be applied to 2.6.33-rcX. It has been present in the > wireless-testing code base for 2 months with no trouble reported, thus it should > be safe for inclusion in your kernels. The relevant patch is attached. > Nice solution. What about making it autodetected ? Or is it only a "last resort" with the hopes of getting the issue fixed? Anyway, thanks for the patch. -- Thomas