Date: Wed, 8 Mar 2017 03:18:21 +0530 From: "Jayachandran C." <jchandra@freebsd.org> To: Ian Lepore <ian@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: <CA%2B7sy7ANOxzJXfx62M8c7sq4SsLL3gDxyhSj74QDmupjKsT7mQ@mail.gmail.com> In-Reply-To: <1488817492.18764.14.camel@freebsd.org> 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> <1488817492.18764.14.camel@freebsd.org>
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On Mon, Mar 6, 2017 at 9:54 PM, Ian Lepore <ian@freebsd.org> wrote: > 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 tested on QEMU's emulated pl011 and it works there too. I was thinking that IFLS behaved differently on ThunderX and that is why my original code worked there. But after going thru the spec again, it looks like the FIFO in newer pl011 implementations is 32 entry deep, and that may be real reason why ThunderX did not have any issues. JC.
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