Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756129Ab2HNOl6 (ORCPT ); Tue, 14 Aug 2012 10:41:58 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:21181 "EHLO mailhub1.si.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751444Ab2HNOl5 (ORCPT ); Tue, 14 Aug 2012 10:41:57 -0400 Date: Tue, 14 Aug 2012 16:26:28 +0200 Message-Id: <201208141426.q7EEQSPc003956@localhost.localdomain> From: Christophe Leroy To: Alan Cox , Vitaly Bordug , Marcelo Tosatti CC: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH] Powerpc 8xx CPM_UART delay in receive Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1450 Lines: 35 Hello, I'm not sure who to address this Patch to either It fixes a delay issue with CPM UART driver on Powerpc MPC8xx. The problem is that with the actual code, the driver waits 32 IDLE patterns before returning the received data to the upper level. It means for instance about 1 second at 300 bauds. This fix limits to one byte the waiting period. Signed-off-by: Christophe Leroy --- linux-3.5-vanilla/drivers/tty/serial/cpm_uart/cpm_uart_core.c 2012-07-21 22:58:29.000000000 +0200 +++ linux-3.5/drivers/tty/serial/cpm_uart/cpm_uart_core.c 2012-08-09 17:38:37.000000000 +0200 @@ -798,7 +799,7 @@ cpm_set_scc_fcr(sup); out_be16(&sup->scc_genscc.scc_mrblr, pinfo->rx_fifosize); - out_be16(&sup->scc_maxidl, pinfo->rx_fifosize); + out_be16(&sup->scc_maxidl, 1); out_be16(&sup->scc_brkcr, 1); out_be16(&sup->scc_parec, 0); out_be16(&sup->scc_frmec, 0); @@ -872,7 +873,7 @@ /* Using idle character time requires some additional tuning. */ out_be16(&up->smc_mrblr, pinfo->rx_fifosize); - out_be16(&up->smc_maxidl, pinfo->rx_fifosize); + out_be16(&up->smc_maxidl, 1); out_be16(&up->smc_brklen, 0); out_be16(&up->smc_brkec, 0); out_be16(&up->smc_brkcr, 1); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/