From mboxrd@z Thu Jan 1 00:00:00 1970 From: Manoj Iyer Subject: Re: [PATCH] mmc: Added quirks for Ricoh 1180:e823 lower base clock frequency Date: Mon, 26 Nov 2012 10:42:55 -0600 (CST) Message-ID: References: <1310419715-13254-1-git-send-email-manoj.iyer@canonical.com> <201107131835.25217.arnd@arndb.de> <87obiqa39h.fsf@octavius.laptop.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: <87obiqa39h.fsf@octavius.laptop.org> Sender: linux-pci-owner@vger.kernel.org To: Chris Ball Cc: Manoj Iyer , Arnd Bergmann , linux-kernel@vger.kernel.org, jbarnes@virtuousgeek.org, matsumur@nts.ricoh.co.jp, linux-pci@vger.kernel.org, linux-mmc@vger.kernel.org List-Id: linux-mmc@vger.kernel.org Chris, Do you know what systems produce these errors? I can look and see if we have those for testing your patch. Cheers Manoj On Wed, 21 Nov 2012, Chris Ball wrote: > Hi Manoj, Matsumuro-san, > > On Mon, Jul 18 2011, Manoj Iyer wrote: >> Right, without the patch I get.. >> >> [ 52.526665] mmc0: new SDHC card at address e624 >> [ 52.571228] mmcblk0: mmc0:e624 SD16G 14.8 GiB >> [ 52.591071] mmcblk0: retrying using single block read >> [ 52.593105] mmcblk0: error -84 transferring data, sector 0, nr 8, >> card status 0x900 >> [ 52.593109] end_request: I/O error, dev mmcblk0, sector 0 >> [ 52.594594] mmcblk0: error -84 transferring data, sector 1, nr 7, >> card status 0x900 >> [ 52.594604] end_request: I/O error, dev mmcblk0, sector 1 >> [ 52.602893] quiet_error: 24 callbacks suppressed >> [ 52.602902] Buffer I/O error on device mmcblk0, logical block 0 >> [ 52.605349] ldm_validate_partition_table(): Disk read failed. >> [ 52.605384] Dev mmcblk0: unable to read RDB block 0 >> [ 52.607729] mmcblk0: unable to read partition table >> u@u:~$ >> >> So, I cannot generate any comparison data with this SD card. > > I don't know if you remember this bug, but I have reports from two users > who see "error -84"s on :e823 controllers even with this patch active on > modern ThinkPads. > > Maybe 50MHz isn't low enough sometimes? Is it possible to lower the base > clock further? > > I noticed that the frequency is encoded ine one of the PCI writes: > + * 0x32 - 50Mhz new clock frequency > > So if I get access to one of these systems, I might try lowering that > value (by half, say) and see what happens. But at the moment I haven't > found someone who's willing to try kernel patches yet, and I don't have > one of these systems myself. > > Thanks! > > - Chris. > -- > Chris Ball > One Laptop Per Child > > -- ==================== Manoj Iyer Ubuntu/Canonical Hardware Enablement ====================