Re: System hang when using SetMemoryAttributes

[Michael Zimmermann <sigmaepsilon92@gmail.com>]

> Are you saying your framebuffer does work with cached attributes? That
> would mean the graphics device is DMA coherent, which is actually a
> good thing. What hardware are we talking about here?
yes it does but ofc, it causes glitches since the writes aren't always
synced correctly.
My edk2 port is cross platorm by using PrePi and a function table provided
by another bootloader for hardware communication.

The device that's broken is 'Asus Zenfone 2 Laser ZE550KL' which uses a
'Qualcomm MSM8939 Snapdragon 615' chipset.

On Mon, Sep 26, 2016 at 2:47 PM, Ard Biesheuvel <ard.biesheuvel@linaro.org>
wrote:

> On 26 September 2016 at 05:44, Michael Zimmermann
> <sigmaepsilon92@gmail.com> wrote:
> > I'm thankful for the hint about _WC because it drastically improves the
> > speed on my other devices.
>
> Glad I could be of help.
>
> > Unfortunately, it doesn't fix the device I have problems with. I tested
> all
> > possible attributes and only EFI_MEMORY_WB seems to be working(even
> > EFI_MEMORY_WT is broken).
> >
> > The weird thing is that even if I disable accesses to the framebuffer by
> > disabling all code in the Blt function, it hangs during boot.
> > I really can't explain this behavior.
> >
>
> Are you saying your framebuffer does work with cached attributes? That
> would mean the graphics device is DMA coherent, which is actually a
> good thing. What hardware are we talking about here?
>