On Thu, Mar 24, 2022 at 2:07 AM Paul Menzel <pmenzel@xxxxxxxxxxxxx> wrote: > > Dear Craig, > > > Am 24.03.22 um 02:09 schrieb Craig M: > > I should add some further information: > > > > I have tried using Manjaro KDE, Kubuntu 20 and Kubuntu 18.03 live > > disks and all exhibit this 'tearing' issue. > > > > The problem begins rather early on in the boot sequence while the TUI > > is logging the startup information and continues to be a problem as > > the screen becomes graphic. > > > > I feel that I should be able to rectify this with a setting change. > > > > Again, Thanks for any help. > > Craig. > > In the future, it’d be great if instead of top-posting you used > interleaved style. > > > On 3/24/22, Craig M <cmroanirgo@xxxxxxxxx> wrote: > >> Hi, > >> > >> I'm trying to track down a problem with an ancient graphics device ATI > >> Radeon Mobility 3470. > >> > >> Ubuntu/Kubuntu 18 is shipped kernel 4.18 and the radeon drivers work well. > >> With 18.02 and later it ships with kernel 5.0 and the radeon drivers don't. > >> > >> What I'm seeing is hard to describe. It looks a lot like the scan > >> lines are interleaved and there's a lot of noise. It's not the typical > >> screen tearing, nor is it just snow (black and white noise). I can > >> *just* make out what it being displayed onscreen, but hurts the eyes a > >> lot to try and do so! > >> > >> If I hold the kernel back at 4.18 things are just fine. > >> > >> Some detailed info (from a working 4.18 kernel). Note that the > >> returned information from a 5.x kernel isn't all that much different: > >> > >> $ lshw -c video > >> *-display > >> description: VGA compatible controller > >> product: RV620/M82 [Mobility Radeon HD 3450/3470] > >> vendor: Advanced Micro Devices, Inc. [AMD/ATI] > >> physical id: 0 > >> bus info: pci@0000:01:00.0 > >> version: 00 > >> width: 32 bits > >> clock: 33MHz > >> capabilities: pm pciexpress msi vga_controller bus_master > >> cap_list rom configuration: driver=radeon latency=0 > >> resources: irq:26 memory:c0000000-c7ffffff ioport:9000(size=256) > >> memory:c8020000-c802ffff memory:c0000-dffff > >> > >> > >> $ modinfo radeon > >> > >> filename: > >> /lib/modules/4.18.0-17-generic/kernel/drivers/gpu/drm/radeon/radeon.ko > >> license: GPL and additional rights description: ATI Radeon > >> author: Gareth Hughes, Keith Whitwell, others. > >> > >> ... > >> name: radeon > >> vermagic: 4.18.0-17-generic SMP mod_unload > >> signat: PKCS#7 > >> signer: > >> sig_key: > >> sig_hashalgo: md4 > >> .... > > Looking at the output of `dmesg` might also help. > > >> I'm just trying to track down the driver changes between 4.18 and 5.0 > >> to see what I can do to change settings. Any help would be greatly > >> appreciated. I've had a quick look through > >> https://gitlab.freedesktop.org/xorg/driver/xf86-video-ati but I don't > >> know where to start (as there's no correlation between releases and > >> kernels, from what I can see). > > As switching the Linux kernel version works, you need to look at the > driver in the Linux kernel. As you can easily reproduce your problem, > and you are most likely alone with this old hardware, bisecting will > probably the way to go. First you can try the packages from Ubuntu’s > Kernel PPA [1]. Figuring out, in what version the regression occurs, you > then build the Linux kernel yourself, for example with `make > bindeb-pkg`, and try to find out the exact commit. There should be some > guides on the WWW explaining all this in detail. Yeah, as Paul said, bisecting is probably your best bet. The radeon driver has largely been in maintenance-only mode for the last few years so it hasn't really seen any changes other than misc bug fixes or cross component API changes. Alex > > > Kind regards and good luck, > > Paul > > > PS: It would also be nice to know, if the problem is still present in > Linux 5.17. > > > [1]: https://kernel.ubuntu.com/~kernel-ppa/mainline/
