On Mon, 4 Mar 2019 12:01:29 +0000 Robin Murphy <[email protected]> wrote:
> Hi Thomas, > > On 04/03/2019 11:52, Thomas Zimmermann wrote: > > This is an RFC patch set that adds support for configuring a default CMA > > size, depending on the platform. > > > > At SUSE, our ARM installer image runs on a variety of platforms. One of > > these, the Raspberry Pi 3, requires CMA to be allocated on order to provide > > graphics output. Currently this can be done with the kernel's cma command- > > line parameter, or with a compile-time setting. The cma parameter requires > > user intervention during boot. Using a compile-time constant affects all > > platforms. So both options are undesireable. > > > > This patch set adds a data structure and look-up code to select a default > > CMA size, depending on the device's model name. The kernel's cma parameter > > or a compile-time setting take precedence of the per-device default. > > Is there some issue with specifying a board-specific default CMA region > via the existing DT binding[1]? I assume there are no ACPI concerns in > this particular case. Indeed. Thomas, did you have a look how the installer gets booted on the Raspberry Pi? Are we simply using the pre-installed bootloader in this scenario? Petr T > Robin. > > [1] > Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt > > > For the Raspberry Pi 3, the CMA allocator now reserves 64 MiB (out > > of 1 GiB) by default. We found that this is enough memory to run a > > graphics installer or a simple desktop environment under X11. > > > > Thomas Zimmermann (2): > > kernel/dma: Support device-specific CMA defaults > > kernel/dma: Default to 64 MiB of contiguous memory on Raspberry > > Pi 3 > > > > kernel/dma/contiguous.c | 62 > > +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 > > insertions(+)
pgpI0FOJn3hth.pgp
Description: Digitálnà podpis OpenPGP
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