>-----Original Message----- >From: ext Tony Lindgren [mailto:tony@xxxxxxxxxxx] >Sent: 04 February, 2010 18:11 >To: Kristo Tero (Nokia-D/Tampere) >Cc: linux-omap@xxxxxxxxxxxxxxx >Subject: Re: [PATCH] OMAP3: Serial: Improved sleep logic > >* Tero.Kristo@xxxxxxxxx <Tero.Kristo@xxxxxxxxx> [100203 23:59]: >> >> >> >-----Original Message----- >> >From: ext Tony Lindgren [mailto:tony@xxxxxxxxxxx] >> >Sent: 03 February, 2010 19:50 >> >To: Kristo Tero (Nokia-D/Tampere) >> >Cc: linux-omap@xxxxxxxxxxxxxxx >> >Subject: Re: [PATCH] OMAP3: Serial: Improved sleep logic >> > >> >* Tero Kristo <tero.kristo@xxxxxxxxx> [100202 01:38]: >> >> From: Tero Kristo <tero.kristo@xxxxxxxxx> >> >> >> >> 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. >> > >> >Sounds this is for 2.6.34 merge window and does not contain anything >> >that needs to be fixed for 2.6.33. >> >> Yeah, this only fixes a couple of annoying issues, but >nothing fatal. Also improves power efficiency in some cases >which is a nice to have feature, and basically eases the >development of PM code as the UART does not block the system >from sleeping always. > >Yeah cool. Separate issue, but I wonder if we should also clear >the the first rx character from the fifo to avoid corrupting >the console. Only when the uart clocks are off and and >we get a key press. Would be easy to do just do with one >serial_read_reg(uart->p, UART_RX).. Yeah, I can try to add this change to the code and see what happens. > >Tony > >> >> -Tero >> >> > >> >Regards, >> > >> >Tony >> > >> > >> >> Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxx> >> >> --- >> >> 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@xxxxxxxxxxxxxxx >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > >-- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
