> From: Rob Clark <robdcl...@gmail.com> > Date: Thu, 12 Oct 2017 10:28:43 -0400 > > On Thu, Oct 12, 2017 at 9:50 AM, Alexander Graf <ag...@suse.de> wrote: > > On 10/12/2017 03:40 PM, Rob Clark wrote: > >> > >> On Thu, Oct 12, 2017 at 9:05 AM, Heinrich Schuchardt <xypron.g...@gmx.de> > >> wrote: > >>> > >>> > >>> On 10/12/2017 02:48 PM, Rob Clark wrote: > >>>> > >>>> On Thu, Oct 12, 2017 at 3:15 AM, Alexander Graf <ag...@suse.de> wrote: > >>>>> > >>>>> > >>>>> > >>>>> On 12.10.17 00:07, Rob Clark wrote: > >>>>>> > >>>>>> On Wed, Oct 11, 2017 at 10:45 AM, Alexander Graf <ag...@suse.de> > >>>>>> wrote: > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> On 10.10.17 14:23, Rob Clark wrote: > >>>>>>>> > >>>>>>>> In some cases, it is quite useful to have (for example) EFI on > >>>>>>>> screen > >>>>>>>> but u-boot on serial port. > >>>>>>>> > >>>>>>>> This adds two new optional environment variables, "efiin" and > >>>>>>>> "efiout", > >>>>>>>> which can be used to set EFI console input/output independently of > >>>>>>>> u-boot's input/output. If unset, EFI console will default to stdin/ > >>>>>>>> stdout as before. > >>>>>>>> > >>>>>>>> Signed-off-by: Rob Clark <robdcl...@gmail.com> > >>>>>>> > >>>>>>> > >>>>>>> With this patch, we lose the ability to have the efi in/out go to > >>>>>>> both > >>>>>>> graphical and serial console, right? This is critical functionality > >>>>>>> to > >>>>>>> have, since we don't necessarily know which output/input a user ends > >>>>>>> up > >>>>>>> using. > >>>>>> > >>>>>> > >>>>>> I'll think about how to support iomux.. but some things like console > >>>>>> size are just not going to work properly there. And as long as we fix > >>>>> > >>>>> > >>>>> Yeah, those probably would need to get special cased. > >>>>> > >>>>>> the stdout shenanigans (ie. what I was seeing w/ qemu-x86) you can > >>>>>> simply not set efiout var and have things working as before, so you > >>>>>> don't loose any existing functionality (although, like I said, if the > >>>>>> two different consoles have different sizes things aren't going to > >>>>>> work properly for anything other than simple cases). > >>>>>> > >>>>>> In most cases, the display driver should be able to detect whether a > >>>>>> display is connected.. this is what I've done on dragonboard410c, so > >>>>>> if no display plugged in, 'efiout=vidconsole' fails and you fall back > >>>>>> to serial, else you get efi on screen like you would on a "real" > >>>>>> computer. For boards that have a display driver that isn't able to do > >>>>>> the basic check of whether a cable is plugged in, just don't set > >>>>>> "efiout" (or fix the display driver) ;-) > >>>>> > >>>>> > >>>>> Are you sure that's what happens on a "real" computer? As far as I > >>>>> remember from all ARM servers running edk2 based firmware that I've > >>>>> touched so far, the default is always to display on serial *and* > >>>>> graphical output at the same time. > >>>> > >>>> > >>>> Well, I suppose some of the arm64 server vendors have done a better > >>>> job than others on firmware.. you'd hope they would probe EDID, and > >>>> report correct console dimensions based on display resolution, etc. > >>>> > >>>> Doing both serial and display works for simple stuff, but it goes > >>>> badly once the efi payload starts trying to change the cursor position > >>>> and write to specific parts of the screen (which both Shell.efi and > >>>> grub try to do). > >>>> > >>>> BR, > >>>> -R > >>>> > >>> Hello Rob, > >>> > >>> I do not know which program you use for connecting to your serial > >>> console. I > >>> use minicom which is a Debian/Ubuntu package. I had no problem using > >>> grub, > >>> vim, nano or any other console program. > >>> > >>> Minicom just provides a VT100 emulation and that is close enough to what > >>> Linux expects. > >> > >> fwiw, I generally use kermit so my terminal emulator is whatever > >> "xterm" type app I'm using. (Currently a big fan of Tilix).. but that > >> isn't so much the issue.. > >> > >>> So I would not see what should be so special about Shell.efi. > >> > >> I'm not explaining the problem well, but you can see basically the > >> same issue if you resize your terminal emulator to something smaller > >> than what grub/shell/etc think you are using. > >> > >> I guess if they just fall back to assuming 80x25 like agraf mentioned, > >> that would kind of work. It just means shell or grub will only use > >> the tiny upper-left corner of your monitor. > >> > >>> My U-Boot system all have video but I never have a monitor connected. > >>> > >>> So being able to use serial even if video is available is a necessity. > >> > >> If the video driver doesn't detect that it is unconnected, someone > >> should really fix that, otherwise you'll have problems booting an > >> image where grub tries to use gfxterm if GOP is present (but we are > >> really getting off topic here) > >> > >> Either way, you still have the option of not setting efiout (or > >> setting it to serial) > >> > >> But for end users (at least of boards that I care about), if they plug > >> in a monitor they should get grub on screen. Not everyone has a > >> serial cable attached. > > > > > > I fully agree there. The same applies the other way around too. Even if they > > have a monitor attached, they should get grub on serial if serial is a valid > > output :). Just attaching a monitor doesn't mean you only use that monitor > > to control the system. > > We could, I suppose, try probing the serial console's size, as an > approximation of hotplug detect for serial. If we timeout without > getting a response, assume no serial console.
By spitting out random control characters and hope they match the terminal emulation on the other end? Sounds like a bad idea to me to do that by default. Or would you only do it for EFI payload that uses more than just the EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL? That might be acceptable. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
