Hi Konrad, Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxx> writes: > On 17.12.2021 13:57, Felipe Balbi wrote: >> From: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxx> >> >> Hi folks, >> >> I'm trying to enable the framebuffer on Microsoft Surface Duo. Looking >> through some internal docs, it came to my attention that the bootloader >> will fill up the framebuffer address and size to a memory node names >> splash_region. Adding the node, I can see the address of the >> framebuffer. Creating the relevant framebuffer device using >> simple-framebuffer, I can't see it working. Tried dd if=/dev/urandom >> of=/dev/fb0 and fb-test. None of which manage to get rid of what's >> already on the screen, put there by the bootloader (platform Logo). >> >> Wondering if any of you have seen a behavior such as this and how did >> you manage to get framebuffer working on SM8150 (I see at least Sony >> Xperia has the node). >> >> Felipe Balbi (2): >> arm64: boot: dts: qcom: sm8150: add a label for reserved-memory >> arm64: boot: dts: qcom: surface duo: add minimal framebuffer >> >> .../dts/qcom/sm8150-microsoft-surface-duo.dts | 19 +++++++++++++++++++ >> arch/arm64/boot/dts/qcom/sm8150.dtsi | 2 +- >> 2 files changed, 20 insertions(+), 1 deletion(-) > > Hi, > > > this issue is totally unique to the Duo and your bootloader configuration. > > > Gus (CCd, co-author of Lumia 950/XL patches) and I were dissecting > this precise issue (albeit for a different usecase) and in our testing > it turned out that XBL likely kills the display stack upon exiting > Boot Services and jumping to LinuxLoader. This may be a bug that comes > from the legacy of this device, as exiting Boot Services would be > rather undesirable in that scenario.. This is very nice background information which I didn't have. Thanks :-) > One fix would be to ask the bootloader team to look into it and fix it > from there, otherwise you'd have to bring up the display using the > DPU1 driver, or perhaps in a third-stage-bootloader (pls don't do it I'll give DPU1 a shot, thanks for the pointer > for the sanity of us all :D) no 3rd stages :-) -- balbi
