From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH] OMAP3: Serial: Improved sleep logic Date: Thu, 04 Feb 2010 13:19:39 -0800 Message-ID: <87ljf83dhw.fsf@deeprootsystems.com> References: <1265110224-29473-1-git-send-email-tero.kristo@nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-px0-f182.google.com ([209.85.216.182]:60157 "EHLO mail-px0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758282Ab0BDVTm (ORCPT ); Thu, 4 Feb 2010 16:19:42 -0500 Received: by pxi12 with SMTP id 12so3336293pxi.33 for ; Thu, 04 Feb 2010 13:19:41 -0800 (PST) In-Reply-To: <1265110224-29473-1-git-send-email-tero.kristo@nokia.com> (Tero Kristo's message of "Tue\, 2 Feb 2010 13\:30\:24 +0200") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tero Kristo Cc: linux-omap@vger.kernel.org Tero Kristo writes: > From: Tero Kristo > > Only RX interrupt will now kick the sleep prevent timer. In addition, TX > fifo status is checked before disabling clocks, this will prevent occasional > garbage being printed on serial line. Smartidle is also disabled while > entering idle if we have data in the transmit buffer, because having this > enabled will prevent wakeups from the TX interrupt, and this causes > pauses while sending large blocks of data. > > Signed-off-by: Tero Kristo After doing some more testing with this, something is not quite right still. I haven't taken the time to debug further, but with this patch on top of the current PM branch, the timer seems to expire and disable clocks whether or not there is UART activity. In particular, using a UART1 console on OMAP3EVM, I notice that while typing longer commands (that take more that seconds to type), I notice that I loose chars in the middle of typing. /me doesn't like. So I won't be applying this to the PM branch until we can figure out what's happening here. Kevin > --- > arch/arm/mach-omap2/serial.c | 19 +++++++++++++++---- > 1 files changed, 15 insertions(+), 4 deletions(-) > > diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c > index 777e802..e11dfe9 100644 > --- a/arch/arm/mach-omap2/serial.c > +++ b/arch/arm/mach-omap2/serial.c > @@ -317,7 +317,8 @@ static void omap_uart_allow_sleep(struct omap_uart_state *uart) > if (!uart->clocked) > return; > > - omap_uart_smart_idle_enable(uart, 1); > + if (serial_read_reg(uart->p, UART_LSR) & UART_LSR_TEMT) > + omap_uart_smart_idle_enable(uart, 1); > uart->can_sleep = 1; > del_timer(&uart->timer); > } > @@ -335,7 +336,11 @@ void omap_uart_prepare_idle(int num) > > list_for_each_entry(uart, &uart_list, node) { > if (num == uart->num && uart->can_sleep) { > - omap_uart_disable_clocks(uart); > + if (serial_read_reg(uart->p, UART_LSR) & > + UART_LSR_TEMT) > + omap_uart_disable_clocks(uart); > + else > + omap_uart_smart_idle_enable(uart, 0); > return; > } > } > @@ -407,8 +412,14 @@ int omap_uart_can_sleep(void) > static irqreturn_t omap_uart_interrupt(int irq, void *dev_id) > { > struct omap_uart_state *uart = dev_id; > + u8 lsr; > > - omap_uart_block_sleep(uart); > + lsr = serial_read_reg(uart->p, UART_LSR); > + /* Check for receive interrupt */ > + if (lsr & UART_LSR_DR) > + omap_uart_block_sleep(uart); > + if (lsr & UART_LSR_TEMT && uart->can_sleep) > + omap_uart_smart_idle_enable(uart, 1); > > return IRQ_NONE; > } > -- > 1.5.4.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html