On Tue, Jul 17, 2018 at 4:02 PM Rob Herring <robh@xxxxxxxxxx> wrote: > On Tue, Jul 17, 2018 at 1:47 AM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > > On Tue, Jul 17, 2018 at 12:50 AM Rob Herring <robh@xxxxxxxxxx> wrote: > > > On Mon, Jul 16, 2018 at 3:23 AM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > > > Why don't you just define a 'vga-connector' node > > > > Because this is not a VGA connector, it is just the VGA resolution. > > In other circumstances I do use it. > > It's not a panel either. A connector is something with variable > resolution. A panel is fixed resolution. Which do you want? OK I get it, I think... it makes a lot of sense. For an emulated machine it's pretty much up to the sophistication of the emulation. But variable is the best answer I assume. > > Apart from being a user experience horror story, that requires > > a VGA connector bridge, as per above. (It's the EDID code that > > does that command line parsing.) And that requires lying about > > having a VGA connector bridge. > > Because you have to set the resolution on the kernel command line? I'm > open to having a default resolution for the connector in DT. OK seems like that old virtual encoder that Liviu dug up is something we should dust off and use then. > > Sudeep at ARM says it does not emulate any DAC bridge such > > as found in the Versatile Express machine family. It just expects > > to have the right resolution parameters written into the registers > > of the PL111, which in turn of course can only get it from a > > panel or bridge driver of some sort. > > So putting *anything* in DT is a lie... The virtual encoder seems like telling the truth so I should work on that. > Having a way to set the default display resolution in QEMU would be > nice. I've hacked around that when using virgl. QEMU is pretending to not provide a resolution, but an emulated monitor identified over I2C with EDID. For the Vexpress emulation we connected the SII9022 DVI encoder hw/display/sii9022.c to the QEMU DDC/EDID channel provider in hw/i2c/i2c-ddc.c. This thing provides a conjured EDID blob to the DRM EDID logic when using Linux. It currently returns a simple 21" LCD VGA monitor probably resulting in 1024x768 resolution. By extending and refactoring this code, we could provide a more ealborate "monitor" down to the emulator. The type of monitor implies the resolution. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
