[Qemu-discuss] Black screen when emulating Raspberry Pi with qemu 2.5
Hello, after some minor tweaks to pixman I got qemu 2.5.0 to compile and run on OS X 10.11. I'm trying to set it up to emulate a Raspberry Pi for development, but I can't get it to boot from the raspbian linux image. I'm using: 2016-02-26-raspbian-jessie.img downloaded from https://www.raspberrypi.org/downloads/raspbian/ kernel-qemu-4.1.13-jessie downloaded from https://github.com/dhruvvyas90/qemu-rpi-kernel If I start with: /usr/local/qemu/bin/qemu-system-arm -M versatilepb -m 512 -cpu arm1176 -no-reboot -kernel kernel-qemu-4.1.13-jessie -hda 2016-02-26-raspbian-jessie.img -serial stdio it prints "Uncompressing Linux... done, booting the kernel." and then the kernel hangs since it can't find a root fs: https://www.dropbox.com/s/ogmhcyser53ko32/Sk%C3%A4rmklipp%202016-03-08%2012.53.21.png The problem is that if I try to add any kernel boot options with -append, even if it's just "panic=1", all I get is a black screen for a few seconds and then it exits: /usr/local/qemu/bin/qemu-system-arm -M versatilepb -m 512 -cpu arm1176 -no-reboot -kernel kernel-qemu-4.1.13-jessie -hda 2016-02-26-raspbian-jessie.img -serial stdio -append "panic=1" https://www.dropbox.com/s/e11mzvdjcpcfylf/Sk%C3%A4rmklipp%202016-03-08%2012.57.22.png If i use "root=/dev/sda" I still only get a black screen, but it doesn't exit after a few seconds so maybe it's booting? I also tried compiling the latest git version, and the results are the same. I tried the experimental raspi2 machine too, but that just gives me a debugger prompt. I'm completely new to qemu so any pointers are welcome. -- Per Olofsson magerv...@fastmail.fm
Re: [Qemu-discuss] Black screen when emulating Raspberry Pi with qemu 2.5
On 08/03/2016 13:01, Per Olofsson wrote: Hello, after some minor tweaks to pixman I got qemu 2.5.0 to compile and run on OS X 10.11. I'm trying to set it up to emulate a Raspberry Pi for development, but I can't get it to boot from the raspbian linux image. I'm using: 2016-02-26-raspbian-jessie.img downloaded from https://www.raspberrypi.org/downloads/raspbian/ kernel-qemu-4.1.13-jessie downloaded from https://github.com/dhruvvyas90/qemu-rpi-kernel If I start with: /usr/local/qemu/bin/qemu-system-arm -M versatilepb -m 512 -cpu arm1176 -no-reboot -kernel kernel-qemu-4.1.13-jessie -hda 2016-02-26-raspbian-jessie.img -serial stdio Are you sure -hda filename.img causes filename.img to be used as a virtual *SDCard* (which is what Raspberry Pi has)? it prints "Uncompressing Linux... done, booting the kernel." and then the kernel hangs since it can't find a root fs: https://www.dropbox.com/s/ogmhcyser53ko32/Sk%C3%A4rmklipp%202016-03-08%2012.53.21.png The problem is that if I try to add any kernel boot options with -append, even if it's just "panic=1", all I get is a black screen for a few seconds and then it exits: /usr/local/qemu/bin/qemu-system-arm -M versatilepb -m 512 -cpu arm1176 -no-reboot -kernel kernel-qemu-4.1.13-jessie -hda 2016-02-26-raspbian-jessie.img -serial stdio -append "panic=1" https://www.dropbox.com/s/e11mzvdjcpcfylf/Sk%C3%A4rmklipp%202016-03-08%2012.57.22.png Don't know about that. If i use "root=/dev/sda" I still only get a black screen, but it doesn't exit after a few seconds so maybe it's booting? On the Raspberry Pi, root is not the whole SDcard, but a partition on it. root may even be a subitem within the first partition on the SDcard, I don't remember right now, it depends on the instructions for putting that .img file on a physical SDcard for booting a real Raspberry. I also tried compiling the latest git version, and the results are the same. I tried the experimental raspi2 machine too, but that just gives me a debugger prompt. I'm completely new to qemu so any pointers are welcome. In general, a real Raspberry Pi 1 boots like this: 1. ROM (not EPROM/Flash) code inside the Broadcom chip connects to the SDcard. 2. ROM looks on the first (FAT) partition for a magical file with a proprietary boot blob and copies the beginning of that to RAM. 3. The proprietary boot blob bootstraps the on-chip proprietary GPU and other global CPU features, then chains to the Linux kernel, using a config file on the FAT partition to specify part of the Linux command line). 4. The Linux kernel loads on the pre-initialized CPU and accesses the pre-initialized GPU for display output. 5. At some point in the boot process (maybe the kernel phase, maybe a script on an initrd) mounts the "ext2, ext3 or ext4" partition or file as Linux root, then proceeds with a mostly ordinary Debian boot process. Enjoy Jakob -- Jakob Bohm, CIO, Partner, WiseMo A/S. https://www.wisemo.com Transformervej 29, 2860 Søborg, Denmark. Direct +45 31 13 16 10 This public discussion message is non-binding and may contain errors. WiseMo - Remote Service Management for PCs, Phones and Embedded
Re: [Qemu-discuss] Black screen when emulating Raspberry Pi with qemu 2.5
On Tue, Mar 8, 2016, at 01:29 PM, Jakob Bohm wrote: > On 08/03/2016 13:01, Per Olofsson wrote: > > If I start with: > > > >/usr/local/qemu/bin/qemu-system-arm -M versatilepb -m 512 -cpu arm1176 > >-no-reboot -kernel kernel-qemu-4.1.13-jessie -hda > >2016-02-26-raspbian-jessie.img -serial stdio > Are you sure -hda filename.img causes filename.img to be used > as a virtual *SDCard* (which is what Raspberry Pi has)? No, this mounts the image as an IDE device, but my goal at this point is just to boot raspbian linux rather than full emulation. As I was typing this reply and double checking everything I managed to see a point that I'd overlooked before: https://github.com/dhruvvyas90/qemu-rpi-kernel/wiki#key-notes versatilepb only supports 256 MB of RAM, and trying to run with 512 causes the black screen. Having a console makes things a lot easier, and tells me that it successfully mounts the root filesystem (with root=/dev/sda2) but it panics trying to run init (actually /bin/bash): /usr/local/qemu/bin/qemu-system-arm -kernel kernel-qemu-4.1.13-jessie -cpu arm1176 -m 256 -M versatilepb -no-reboot -serial stdio -hda 2016-02-26-raspbian-jessie.img -append "root=/dev/sda2 panic=0 rw init=/bin/bash" https://www.dropbox.com/s/aopefzzyswl4eyn/Sk%C3%A4rmklipp%202016-03-08%2014.17.03.png Still, progress! -- Per Olofsson magerv...@fastmail.fm
Re: [Qemu-discuss] Black screen when emulating Raspberry Pi with qemu 2.5
With console output fixed it wasn't too hard to make it all work. For future reference, the instructions here had all the necessary pieces of the puzzle: https://github.com/dhruvvyas90/qemu-rpi-kernel/wiki https://github.com/dhruvvyas90/qemu-rpi-kernel/wiki/Emulating-Jessie-image-with-4.1.x-kernel After converting the modified raw image to a qcow2 my final command line for qemu 2.5.0 is: /usr/local/qemu/bin/qemu-system-arm \ -cpu arm1176 \ -m 256 \ -M versatilepb \ -no-reboot \ -kernel kernel-qemu-4.1.13-jessie \ -hda raspbian-jessie-qemu.qcow \ -append "root=/dev/sda2 rootfstype=ext4 rw" \ -serial stdio -- Per Olofsson magerv...@fastmail.fm
