From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH v2] i2c: i801: Fix I2C Block Read on 8-Series/C220 and later Date: Tue, 11 Oct 2016 20:20:45 +0200 Message-ID: <20161011202045.43787f2e@endymion> References: <20161011131327.0eabd227@endymion> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:40566 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753582AbcJKSUw (ORCPT ); Tue, 11 Oct 2016 14:20:52 -0400 In-Reply-To: Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Jarkko Nikula Cc: Linux I2C , Mika Westerberg , Wolfram Sang Hi Jarkko, On Tue, 11 Oct 2016 14:32:55 +0300, Jarkko Nikula wrote: > On 10/11/2016 02:13 PM, Jean Delvare wrote: > > Starting with the 8-Series/C220 PCH (Lynx Point), the SMBus > > controller includes a SPD EEPROM protection mechanism. Once the SPD > > Write Disable bit is set, only reads are allowed to slave addresses > > 0x50-0x57. > > > > However the legacy implementation of I2C Block Read since the ICH5 > > looks like a write, and is therefore blocked by the SPD protection > > mechanism. This causes the eeprom and at24 drivers to fail. > > > > So assume that I2C Block Read is implemented as an actual read on > > these chipsets. I tested it on my Q87 chipset and it seems to work > > just fine. > > > > Signed-off-by: Jean Delvare > > Cc: Jarkko Nikula > > Cc: Mika Westerberg > > Cc: Wolfram Sang > > --- > > Changes since v1: > > * Rebased on Linus' latest tree. > > > > Jarkko, still no information about this from your Windows or hardware > > folks? > > No update, in fact some of the contacts have left the company :-( What do we do then? Without this patch, I2C Block Read doesn't work at all on recent chipsets. I don't think it can be worse with the patch. And it works fine on the few machines I tested on. So I would like this patch to go upstream. My coverage is limited though. Did anyone at Intel test this patch on other (recent) systems? -- Jean Delvare SUSE L3 Support