From: Nicolas Schichan <nschichan@freebox.fr> To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>, linux-serial@vger.kernel.org Cc: tony@atomide.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, balbi@ti.com, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 03/16] tty: serial: 8250_core: read only RX if there is something in the FIFO Date: Mon, 09 Feb 2015 14:34:42 +0100 [thread overview] Message-ID: <54D8B772.1010405@freebox.fr> (raw) In-Reply-To: <1410377411-26656-4-git-send-email-bigeasy@linutronix.de> On 09/10/2014 09:29 PM, Sebastian Andrzej Siewior wrote: > The serial8250_do_startup() function unconditionally clears the > interrupts and for that it reads from the RX-FIFO without checking if > there is a byte in the FIFO or not. This works fine on OMAP4+ HW like > AM335x or DRA7. > OMAP3630 ES1.1 (which means probably all OMAP3 and earlier) does not like > this: Hello, Sorry to wake up an old thread, but I'm affraid that this patch causes problems on Marvell 88f6282 (Kirkwood). When a caracter is received on the UART while the kernel is printing the boot messages, as soon as the kernel configures the UART for receiving (after root filesystem mount), it gets stuck printing the following message repeatedly: serial8250: too much work for irq29 Once stuck, the reception of another character allows the boot process to finish. >From what I can gather, when we hit that, the UART_IIR_NO_INT is 0 (so the interrupt is raised), but the UART_LSR_DR bit is 0 as well so the UART_RX register is never read to clear the interrupt. We are using the second UART multiplexed on mpps 15 and 16. Reverting this particular patch fixes the issue. We are seing the problem on a 3.18 kernel. Regards, -- Nicolas Schichan Freebox SAS
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From: nschichan@freebox.fr (Nicolas Schichan) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 03/16] tty: serial: 8250_core: read only RX if there is something in the FIFO Date: Mon, 09 Feb 2015 14:34:42 +0100 [thread overview] Message-ID: <54D8B772.1010405@freebox.fr> (raw) In-Reply-To: <1410377411-26656-4-git-send-email-bigeasy@linutronix.de> On 09/10/2014 09:29 PM, Sebastian Andrzej Siewior wrote: > The serial8250_do_startup() function unconditionally clears the > interrupts and for that it reads from the RX-FIFO without checking if > there is a byte in the FIFO or not. This works fine on OMAP4+ HW like > AM335x or DRA7. > OMAP3630 ES1.1 (which means probably all OMAP3 and earlier) does not like > this: Hello, Sorry to wake up an old thread, but I'm affraid that this patch causes problems on Marvell 88f6282 (Kirkwood). When a caracter is received on the UART while the kernel is printing the boot messages, as soon as the kernel configures the UART for receiving (after root filesystem mount), it gets stuck printing the following message repeatedly: serial8250: too much work for irq29 Once stuck, the reception of another character allows the boot process to finish. >From what I can gather, when we hit that, the UART_IIR_NO_INT is 0 (so the interrupt is raised), but the UART_LSR_DR bit is 0 as well so the UART_RX register is never read to clear the interrupt. We are using the second UART multiplexed on mpps 15 and 16. Reverting this particular patch fixes the issue. We are seing the problem on a 3.18 kernel. Regards, -- Nicolas Schichan Freebox SAS
next prev parent reply other threads:[~2015-02-09 13:43 UTC|newest] Thread overview: 236+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-09-10 19:29 [PATCH 00/16 v9] omap 8250 based uart + DMA Sebastian Andrzej Siewior 2014-09-10 19:29 ` Sebastian Andrzej Siewior 2014-09-10 19:29 ` Sebastian Andrzej Siewior 2014-09-10 19:29 ` [PATCH 01/16] tty: serial: 8250_core: allow to set ->throttle / ->unthrottle callbacks Sebastian Andrzej Siewior 2014-09-10 19:29 ` Sebastian Andrzej Siewior 2014-09-10 19:29 ` [PATCH 02/16] tty: serial: 8250_core: add run time pm Sebastian Andrzej Siewior 2014-09-10 19:29 ` Sebastian Andrzej Siewior 2014-09-10 19:29 ` Sebastian Andrzej Siewior 2014-09-29 9:46 ` Frans Klaver 2014-09-29 9:46 ` Frans Klaver 2014-09-29 9:46 ` Frans Klaver 2014-09-29 13:39 ` Sebastian Andrzej Siewior 2014-09-29 13:39 ` Sebastian Andrzej Siewior 2014-09-10 19:29 ` [PATCH 03/16] tty: serial: 8250_core: read only RX if there is something in the FIFO Sebastian Andrzej Siewior 2014-09-10 19:29 ` Sebastian Andrzej Siewior 2015-02-09 13:34 ` Nicolas Schichan [this message] 2015-02-09 13:34 ` Nicolas Schichan 2015-02-09 23:34 ` Peter Hurley 2015-02-09 23:34 ` Peter Hurley 2015-02-10 9:32 ` Sebastian Andrzej Siewior 2015-02-10 9:32 ` Sebastian Andrzej Siewior 2015-02-10 12:04 ` Nicolas Schichan 2015-02-10 12:04 ` Nicolas Schichan 2015-02-10 17:46 ` Peter Hurley 2015-02-10 17:46 ` Peter Hurley 2015-02-11 20:01 ` Peter Hurley 2015-02-11 20:01 ` Peter Hurley 2015-02-11 20:03 ` Tony Lindgren 2015-02-11 20:03 ` Tony Lindgren 2015-02-11 20:03 ` Tony Lindgren 2015-02-11 20:42 ` Peter Hurley 2015-02-11 20:42 ` Peter Hurley 2015-02-12 8:45 ` Sebastian Andrzej Siewior 2015-02-12 8:45 ` Sebastian Andrzej Siewior 2015-02-12 9:40 ` Russell King - ARM Linux 2015-02-12 9:40 ` Russell King - ARM Linux 2015-02-12 16:32 ` Peter Hurley 2015-02-12 16:32 ` Peter Hurley 2015-02-12 19:23 ` Sebastian Andrzej Siewior 2015-02-12 19:23 ` Sebastian Andrzej Siewior 2015-02-12 19:55 ` Peter Hurley 2015-02-12 19:55 ` Peter Hurley 2015-02-12 20:34 ` Sebastian Andrzej Siewior 2015-02-12 20:34 ` Sebastian Andrzej Siewior 2015-02-13 18:51 ` Sebastian Andrzej Siewior 2015-02-13 18:51 ` Sebastian Andrzej Siewior 2015-02-13 23:15 ` Russell King - ARM Linux 2015-02-13 23:15 ` Russell King - ARM Linux 2015-02-15 17:32 ` [PATCH] serial: 8250: Revert "tty: serial: 8250_core: read only RX if there is something in the FIFO" Sebastian Andrzej Siewior 2015-02-15 17:32 ` Sebastian Andrzej Siewior 2015-05-12 20:25 ` Tony Lindgren 2015-05-12 20:25 ` Tony Lindgren 2014-09-10 19:29 ` [PATCH 04/16] tty: serial: 8250_core: use the ->line argument as a hint in serial8250_find_match_or_unused() Sebastian Andrzej Siewior 2014-09-10 19:29 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 05/16] tty: serial: 8250_core: remove UART_IER_RDI in serial8250_stop_rx() Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-11 11:19 ` Heikki Krogerus 2014-09-11 11:19 ` Heikki Krogerus 2014-09-10 19:30 ` [PATCH 06/16] tty: serial: Add 8250-core based omap driver Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-11 11:57 ` Peter Hurley 2014-09-11 11:57 ` Peter Hurley 2014-09-11 11:57 ` Peter Hurley 2014-09-16 17:01 ` Sebastian Andrzej Siewior 2014-09-16 17:01 ` Sebastian Andrzej Siewior 2014-09-16 17:01 ` Sebastian Andrzej Siewior 2014-09-29 9:38 ` Frans Klaver 2014-09-29 9:38 ` Frans Klaver 2014-09-29 9:38 ` Frans Klaver 2014-09-29 13:27 ` Sebastian Andrzej Siewior 2014-09-29 13:27 ` Sebastian Andrzej Siewior 2014-09-29 13:34 ` Frans Klaver 2014-09-29 13:34 ` Frans Klaver 2014-09-10 19:30 ` [PATCH 07/16] tty: serial: 8250_dma: handle error on TX submit Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 08/16] tty: serial: 8250_dma: enqueue RX dma again on completion Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 09/16] tty: serial: 8250_dma: Add a TX trigger workaround for AM33xx Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-11 11:17 ` Heikki Krogerus 2014-09-11 11:17 ` Heikki Krogerus 2014-09-11 11:17 ` Heikki Krogerus 2014-09-11 11:42 ` Sebastian Andrzej Siewior 2014-09-11 11:42 ` Sebastian Andrzej Siewior 2014-09-11 11:42 ` Sebastian Andrzej Siewior 2014-09-11 12:32 ` Peter Hurley 2014-09-11 12:32 ` Peter Hurley 2014-09-11 12:50 ` Sebastian Andrzej Siewior 2014-09-11 12:50 ` Sebastian Andrzej Siewior 2014-09-11 14:35 ` Peter Hurley 2014-09-11 14:35 ` Peter Hurley 2014-09-11 14:35 ` Peter Hurley 2014-09-15 17:01 ` Sebastian Andrzej Siewior 2014-09-15 17:01 ` Sebastian Andrzej Siewior 2014-09-16 16:55 ` Sebastian Andrzej Siewior 2014-09-16 16:55 ` Sebastian Andrzej Siewior 2014-09-16 16:55 ` Sebastian Andrzej Siewior 2014-09-17 12:20 ` Peter Hurley 2014-09-17 12:20 ` Peter Hurley 2014-09-17 16:25 ` Sebastian Andrzej Siewior 2014-09-17 16:25 ` Sebastian Andrzej Siewior 2014-09-17 16:25 ` Sebastian Andrzej Siewior 2014-09-29 16:15 ` Sebastian Andrzej Siewior 2014-09-29 16:15 ` Sebastian Andrzej Siewior 2014-09-11 15:11 ` Frans Klaver 2014-09-11 15:11 ` Frans Klaver 2014-09-11 15:11 ` Frans Klaver 2014-09-11 16:04 ` Sebastian Andrzej Siewior 2014-09-11 16:04 ` Sebastian Andrzej Siewior 2014-09-11 17:04 ` Frans Klaver 2014-09-11 17:04 ` Frans Klaver 2014-09-12 7:23 ` Sebastian Andrzej Siewior 2014-09-12 7:23 ` Sebastian Andrzej Siewior 2014-09-12 9:40 ` Frans Klaver 2014-09-12 9:40 ` Frans Klaver 2014-09-12 9:51 ` Sebastian Andrzej Siewior 2014-09-12 9:51 ` Sebastian Andrzej Siewior 2014-09-12 10:28 ` Frans Klaver 2014-09-12 10:28 ` Frans Klaver 2014-09-12 10:28 ` Frans Klaver 2014-09-15 16:42 ` Sebastian Andrzej Siewior 2014-09-15 16:42 ` Sebastian Andrzej Siewior 2014-09-16 9:05 ` Frans Klaver 2014-09-16 9:05 ` Frans Klaver 2014-09-16 9:05 ` Frans Klaver 2014-09-16 12:42 ` Frans Klaver 2014-09-16 12:42 ` Frans Klaver 2014-09-16 12:42 ` Frans Klaver 2014-09-16 14:23 ` Frans Klaver 2014-09-16 14:23 ` Frans Klaver 2014-09-16 14:23 ` Frans Klaver 2014-09-17 10:28 ` Frans Klaver 2014-09-17 10:28 ` Frans Klaver 2014-09-17 10:28 ` Frans Klaver 2014-09-21 20:41 ` Sebastian Andrzej Siewior 2014-09-21 20:41 ` Sebastian Andrzej Siewior 2014-09-21 20:41 ` Sebastian Andrzej Siewior 2014-09-22 9:28 ` Frans Klaver 2014-09-22 9:28 ` Frans Klaver 2014-09-22 9:28 ` Frans Klaver 2014-09-24 7:56 ` Sebastian Andrzej Siewior 2014-09-24 7:56 ` Sebastian Andrzej Siewior 2014-09-25 15:14 ` Sebastian Andrzej Siewior 2014-09-25 15:14 ` Sebastian Andrzej Siewior 2014-09-25 15:18 ` Frans Klaver 2014-09-25 15:18 ` Frans Klaver 2014-09-29 8:50 ` Frans Klaver 2014-09-29 8:50 ` Frans Klaver 2014-09-29 8:50 ` Frans Klaver 2014-09-29 9:54 ` Sebastian Andrzej Siewior 2014-09-29 9:54 ` Sebastian Andrzej Siewior 2014-09-29 10:30 ` Frans Klaver 2014-09-29 10:30 ` Frans Klaver 2014-09-29 10:30 ` Frans Klaver 2014-09-30 8:44 ` Frans Klaver 2014-09-30 8:44 ` Frans Klaver 2014-09-30 8:44 ` Frans Klaver 2014-10-02 10:27 ` Sebastian Andrzej Siewior 2014-10-02 10:27 ` Sebastian Andrzej Siewior 2014-10-02 10:27 ` Sebastian Andrzej Siewior 2014-10-13 14:55 ` Frans Klaver 2014-10-13 14:55 ` Frans Klaver 2014-10-13 14:55 ` Frans Klaver 2014-09-23 17:03 ` Peter Hurley 2014-09-23 17:03 ` Peter Hurley 2014-09-24 7:53 ` Sebastian Andrzej Siewior 2014-09-24 7:53 ` Sebastian Andrzej Siewior 2014-09-25 10:42 ` Sebastian Andrzej Siewior 2014-09-25 10:42 ` Sebastian Andrzej Siewior 2014-09-25 11:31 ` Peter Hurley 2014-09-25 11:31 ` Peter Hurley 2014-09-25 13:11 ` Sebastian Andrzej Siewior 2014-09-25 13:11 ` Sebastian Andrzej Siewior 2014-09-25 13:11 ` Sebastian Andrzej Siewior 2014-09-17 16:34 ` Sebastian Andrzej Siewior 2014-09-17 16:34 ` Sebastian Andrzej Siewior 2014-09-17 16:34 ` Sebastian Andrzej Siewior 2014-09-19 10:22 ` Heikki Krogerus 2014-09-19 10:22 ` Heikki Krogerus 2014-09-19 10:22 ` Heikki Krogerus 2014-09-19 10:58 ` Sebastian Andrzej Siewior 2014-09-19 10:58 ` Sebastian Andrzej Siewior 2014-09-19 11:25 ` Peter Hurley 2014-09-19 11:25 ` Peter Hurley 2014-09-22 7:46 ` Heikki Krogerus 2014-09-22 7:46 ` Heikki Krogerus 2014-09-25 9:24 ` Sebastian Andrzej Siewior 2014-09-25 9:24 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 10/16] tty: serial: 8250_dma: optimize the xmit path due to UART_BUG_DMA_TX Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 11/16] tty: serial: 8250_dma: keep own book keeping about RX transfers Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 12/16] tty: serial: 8250_dma: handle the UART RDI event while DMA remains idle Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-29 9:23 ` Frans Klaver 2014-09-29 9:23 ` Frans Klaver 2014-09-29 9:23 ` Frans Klaver 2014-09-10 19:30 ` [PATCH 13/16] tty: serial: 8250_dma: add pm runtime Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-29 9:26 ` Frans Klaver 2014-09-29 9:26 ` Frans Klaver 2014-09-29 9:26 ` Frans Klaver 2014-09-29 9:56 ` Sebastian Andrzej Siewior 2014-09-29 9:56 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 14/16] arm: dts: am33xx: add DMA properties for UART Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 15/16] arm: dts: dra7: " Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-10 19:30 ` [PATCH 16/16] tty: serial: 8250: omap: add dma support Sebastian Andrzej Siewior 2014-09-10 19:30 ` Sebastian Andrzej Siewior 2014-09-12 22:43 ` [PATCH 00/16 v9] omap 8250 based uart + DMA Tony Lindgren 2014-09-12 22:43 ` Tony Lindgren 2014-09-12 22:43 ` Tony Lindgren 2014-09-15 11:50 ` Sebastian Andrzej Siewior 2014-09-15 11:50 ` Sebastian Andrzej Siewior 2014-09-15 11:50 ` Sebastian Andrzej Siewior 2014-09-16 12:57 ` Sebastian Andrzej Siewior 2014-09-16 12:57 ` Sebastian Andrzej Siewior 2014-09-16 12:57 ` Sebastian Andrzej Siewior 2014-09-16 16:48 ` Tony Lindgren 2014-09-16 16:48 ` Tony Lindgren 2014-09-16 21:30 ` Tony Lindgren 2014-09-16 21:30 ` Tony Lindgren 2014-09-16 21:30 ` Tony Lindgren 2014-09-17 8:38 ` Sebastian Andrzej Siewior 2014-09-17 8:38 ` Sebastian Andrzej Siewior 2014-09-17 9:05 ` Sebastian Andrzej Siewior 2014-09-17 9:05 ` Sebastian Andrzej Siewior 2014-09-26 16:02 ` Greg KH 2014-09-26 16:02 ` Greg KH 2014-09-26 16:02 ` Greg KH
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