From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753417AbYHBGgr (ORCPT ); Sat, 2 Aug 2008 02:36:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752008AbYHBGgh (ORCPT ); Sat, 2 Aug 2008 02:36:37 -0400 Received: from esbens.latnet.lv ([92.240.66.74]:53462 "EHLO esbens.latnet.lv" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752005AbYHBGgg (ORCPT ); Sat, 2 Aug 2008 02:36:36 -0400 X-Greylist: delayed 1855 seconds by postgrey-1.27 at vger.kernel.org; Sat, 02 Aug 2008 02:36:36 EDT From: Aivils Stoss To: linux-input@vger.kernel.org, jkosina@suse.cz, linux-kernel@vger.kernel.org, linuxconsole-dev@lists.sourceforge.net Subject: PROBLEM: USB keyboards works only 4 per PC host port Date: Sat, 2 Aug 2008 07:05:31 +0100 User-Agent: KMail/1.9.7 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200808020705.31740.aivils.stoss@latnet.lv> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello All! PROBLEM: USB keyboards works only 4 per PC host port. I work for project which will use 15 - 25 keyboards for children teaching. I discover current Linux 2.6.22 , 2.6.24, 2.6.26 dot not support more than 4 keyboards per single PC host port. All plugged in keyboards are listed as USB devices, listed as input devices, but capable to send input events are only 4 keyboards, no matter where keyboards are plugged in to HUB cascade. All plugged in keyboards switch LED's, when i press NumLock. I tested various usb-hub units and various host PC hardware, i even replace hub power supplay units from 5V1A to 5V3A. All tested cases give best results - 4 keyboards per PC host port and worstest - some PC cannot do more than 8 keyboards at all. I suppose this is Linux kernel bug because i test keyboards under Windows, which support any schema of cascading of usb hubs. I will send any log file if that is necessary, but trouble will pop up in a row of kernels. 2.6.22 didn't have error messages. 2.6.24, 2.6.26 tend to total slow down with eternal reset messages: Jul 25 07:16:00 awork kernel: input,hiddev97: USB HID v1.10 Mouse [USB-compliant keyboard] on usb-0000:00:1d.0-1.1.2 Jul 25 07:16:01 awork kernel: usb 2-1.1.1: reset low speed USB device using uhci_hcd and address 17 Jul 25 07:16:01 awork kernel: usb 2-1.1.2: reset low speed USB device using uhci_hcd and address 18 Jul 25 07:16:02 awork kernel: usb 2-1.1.1: reset low speed USB device using uhci_hcd and address 17 Jul 25 07:16:03 awork kernel: usb 2-1.1.2: reset low speed USB device using uhci_hcd and address 18 Jul 25 07:16:04 awork kernel: usb 2-1.1.1: reset low speed USB device using uhci_hcd and address 17 Jul 25 07:16:05 awork kernel: usb 2-1.1.2: reset low speed USB device using uhci_hcd and address 18 Best regards, Aivils Stoss