From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Starikovskiy Subject: Re: EC Date: Thu, 02 Jul 2009 11:45:13 +0400 Message-ID: <4A4C6589.4070108@suse.de> References: <76780B19A496DC4B80439008DAD7076C03453A5BFC@PDSMSX501.ccr.corp.intel.com> <4A4C51AF.8080206@suse.de> <76780B19A496DC4B80439008DAD7076C03453A5CB9@PDSMSX501.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from charybdis-ext.suse.de ([195.135.221.2]:51030 "EHLO emea5-mh.id5.novell.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753109AbZGBHpN (ORCPT ); Thu, 2 Jul 2009 03:45:13 -0400 In-Reply-To: <76780B19A496DC4B80439008DAD7076C03453A5CB9@PDSMSX501.ccr.corp.intel.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Li, Shaohua" Cc: "lenb@kernel.org" , "linux-acpi@vger.kernel.org" Li, Shaohua =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >=20 >> -----Original Message----- >> From: Alexey Starikovskiy [mailto:astarikovskiy@suse.de] >> Sent: Thursday, July 02, 2009 2:21 PM >> To: Li, Shaohua >> Cc: lenb@kernel.org; linux-acpi@vger.kernel.org >> Subject: Re: EC >> >> Li, Shaohua =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>> Hi, >>> Preempt isn't disabled between ec_burst_enable()/ec_burst_disable()= , so >> it's very likely there is a preemption between them and make the tim= ing >> for burst mode not comply with ACPI spec (400ms for first access and= 50ms >> for subsequent access). >>> We have a system with broken EC and the BIOS engineer identified it= 's >> the timing issue. >>> What's the judgment why Linux doesn't comply with ACPI spec? >> Please disable ec_burst_* and check again. Judgement is that ec_burs= t_* is >> irrelevant to the protocol. > What did you about 'irrelevant to the protocol'? This is what the spe= c defines. I mean, that EC may drop out of burst mode if timeout happens, and it s= hould not change the flow of reads and writes to EC (the protocol). More, EC should work= properly even if we do not enter burst mode at all (my suggestion to disable calls to bu= rst functions).=20 >=20 >> What platform and what other symptoms do you have? How exactly this = EC is >> broken? > The temperature is wrong when we get it from reading EC. The BIOS eng= ineer measured > A lot of EC timeout in EC firmware, and they measured the timing how = Linux accesses > EC. The data they captured in oscilloscope shows Linux has long delay= to access > Ec with burst mode enabled, this occurs more often when another appli= cation is running. Do they have any document about implemented EC timeouts? State diagram?= Other than burst timeout, do they have any other timeouts? What happen= s if they get timeout, do they abort transaction? What do they write in= status register? Do they send GPE? Please collect as much as you can, I was looking for = such info for a very long time. Thanks, Alex. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html