Date: Mon, 06 Mar 2017 09:24:52 -0700 From: Ian Lepore <ian@freebsd.org> To: "Jayachandran C." <jchandra@freebsd.org> Cc: Oleksandr Tymoshenko <gonzo@id.bluezbox.com>, freebsd-arm@freebsd.org, Michael Tuexen <tuexen@fh-muenster.de> Subject: Re: Odd-looking serial console prompt on RPI2 Message-ID: <1488817492.18764.14.camel@freebsd.org> In-Reply-To: <CA%2B7sy7D0ctonL26mchbpyDL-CrcyW%2B5F9CYsQ9UwagR4UcoK7g@mail.gmail.com> References: <20170227195647.GA91329@www.zefox.net> <20170301200112.ymwkfd64tzz5f3b2@mutt-hbsd> <4194F030-4E5C-4EB6-82D7-FD725E3B7CEF@fh-muenster.de> <20170302000334.GA99403@www.zefox.net> <1488419304.60166.26.camel@freebsd.org> <20170302020116.GA98466@bluezbox.com> <1488420309.60166.32.camel@freebsd.org> <CA%2B7sy7Bv=-2mx2MJP18ZnbNp2yO2hKukw=KALn711txaxsk=rg@mail.gmail.com> <1488664965.69705.24.camel@freebsd.org> <CA%2B7sy7D0ctonL26mchbpyDL-CrcyW%2B5F9CYsQ9UwagR4UcoK7g@mail.gmail.com>
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On Mon, 2017-03-06 at 13:59 +0530, Jayachandran C. wrote: > Hi Ian, > > On Sun, Mar 5, 2017 at 3:32 AM, Ian Lepore <ian@freebsd.org> wrote: > > > > On Sat, 2017-03-04 at 22:24 +0530, Jayachandran C. wrote: > > > > > > On Thu, Mar 2, 2017 at 7:35 AM, Ian Lepore <ian@freebsd.org> > > > wrote: > > > > > > > > > > > > On Wed, 2017-03-01 at 18:01 -0800, Oleksandr Tymoshenko wrote: > > > > > > > > > > > > > > > Ian Lepore (ian@freebsd.org) wrote: > > > > > > > > > > > > > > > > > > > > > > > > On Wed, 2017-03-01 at 16:03 -0800, bob prohaska wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Wed, Mar 01, 2017 at 09:20:13PM +0100, Michael Tuexen > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Interesting... Let us know what works and what > > > > > > > > doesn't... > > > > > > > > > > > > > > > > Best regards > > > > > > > > Michael > > > > > > > > > > > > > > > As of FreeBSD 12.0-CURRENT (RPI2) #0 r314450: Wed Mar 1 > > > > > > > 14:48:26 > > > > > > > PST > > > > > > > 2017 > > > > > > > the serial console is still corrupt (output truncated, > > > > > > > input > > > > > > > not > > > > > > > echoed > > > > > > > but treated like the enter key). The serial console does > > > > > > > seem to > > > > > > > work > > > > > > > with U-boot and loader, so I don't think it's the > > > > > > > upstream > > > > > > > hardware. > > > > > > > > > > > > > > The HDMI console looks normal and USB keyboard input > > > > > > > seems to > > > > > > > work. > > > > > > > > > > > > > > There have been several updates to /usr/src/sys/dev/uart > > > > > > > and > > > > > > > it > > > > > > > looks > > > > > > > as if kernel updates are still coming. Maybe the job > > > > > > > simply > > > > > > > isn't > > > > > > > done yet. > > > > > > > > > > > > > > bob > > > > > > > > > > > > > It seems like this might be caused by r314318. Can someone > > > > > > having > > > > > > this problem confirm if 314317 works and 314318 fails? > > > > > Tested on my RPi2, 314317 - works, 314318 - broken > > > > > > > > > CC'ing jchandra@. > > > > > > > > I wonder if there is some bad interaction when the same uart is > > > > used as > > > > a console and a tty? > > > I don't have a RPi3 setup to test now, I will look at the code > > > again > > > to see if > > > I can find an issue. > > > > > > Otherwise I will revert the change until we can find why the RPi > > > UART > > > breaks > > > with these changes. > > > > > > Thanks, > > > JC. > > The bugs should be fixed as of r314682. It looks like the bugs > > have > > long been in the pl011 driver, but were masked by having a fifo > > depth > > of 1 byte -- it all sorta worked by accident previously. > Looked thru r314681 and r314682, thanks for fixing this up. > > There seems to be a difference in behavior in IFLS settings on > different > platforms. I did not see a reasonable way to handle the tx fifo being > full > when sc_txbuf is partially used, which is why I skipped this case in > the > original commit - that was a mistake. > > Thanks, > JC. Hmm. Does that imply the changes I made to set the fifo trigger level to 3/4 may not work on some other platforms? I was only able to test on rpi-b. I've always hated the tx interface between the core uart code and the hardware drivers. The idea that when a tx interrupt happens, the hardware code has to accept exactly as many characters as the tx fifo watermark level is just... strange. It's especially hard to work with when a uart device has dma support. But redoing it without breaking every existing driver is hard. -- Ian
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