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Groups > linux.kernel > #1378381
| From | Peter Hurley <peter@hurleysoftware.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: omap uart + dma issues (Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes) |
| Date | 2016-04-14 03:20 +0200 |
| Message-ID | <rnE6S-1XS-3@gated-at.bofh.it> (permalink) |
| References | (4 earlier) <rmOUG-1Pg-21@gated-at.bofh.it> <rmQts-3h1-13@gated-at.bofh.it> <rn9Z7-2vk-9@gated-at.bofh.it> <rngxA-8aq-11@gated-at.bofh.it> <rnqZY-n3-23@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 04/13/2016 04:11 AM, Sekhar Nori wrote: > On Wednesday 13 April 2016 05:30 AM, Peter Hurley wrote: > >>>> - generates spurious uart interrupt for every rx dma transaction >>>> (ie., necessitates acking every UART interrupt, even UART_IIR_NO_INT) >>>> _Even with this workaround_, it still generates spurious interrupt warning >>>> which shuts off interrupts for several ms while logging the error >>>> message to the console, virtually guaranteeing lost data. >>> >>> as I wrote in my other email I think RDI should be disabled with DMA >> >> >> I'll test to see if disabling RDI eliminates the UART_IIR_NO_INT spurious >> interrupts. Ok; disabling UART_IER_RDI eliminates the UART_IIR_NO_INT spurious interrupts. However, disabling RDI disables RX timeout as well, so data just sits in the RX fifo with no way to get it out. AFAICT that's a showstopper. >>> according the Intel manual and I *think* someone here reported that >>> they see the same problem. >> >> Let's confirm with the Intel folks that this is true, which would argue >> for using the omap-style rx dma flow. > > Andy Shevchenko pointed this out here: https://lkml.org/lkml/2016/2/23/588 which Andy noted as well: On 02/23/2016 08:56 AM, Andy Shevchenko wrote: > The problem is that we have no separate bit to control timeout > interrupts from UART.
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Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-05 06:10 +0200
Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes John Ogness <john.ogness@linutronix.de> - 2016-04-11 10:20 +0200
Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-11 20:00 +0200
Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-04-11 20:40 +0200
Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-11 22:20 +0200
Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-04-12 19:10 +0200
Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-12 20:50 +0200
Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-14 18:10 +0200
8250 dma issues ( was Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes) Peter Hurley <peter@hurleysoftware.com> - 2016-04-13 01:30 +0200
Re: 8250 dma issues ( was Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes) One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-04-14 17:10 +0200
Re: 8250 dma issues ( was Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes) Peter Hurley <peter@hurleysoftware.com> - 2016-04-14 20:00 +0200
omap uart + dma issues (Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes) Peter Hurley <peter@hurleysoftware.com> - 2016-04-13 02:10 +0200
Re: omap uart + dma issues (Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes) Sekhar Nori <nsekhar@ti.com> - 2016-04-13 13:20 +0200
Re: omap uart + dma issues (Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes) Peter Hurley <peter@hurleysoftware.com> - 2016-04-14 03:20 +0200
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