Re: [PATCH 2/2] ArmPlatformPkg/PL111LcdArmVExpressLib: use write-combine mapping for VRAM

[Ryan Harkin <ryan.harkin@linaro.org>]

On 6 April 2017 at 12:32, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> On 6 April 2017 at 12:14, Ryan Harkin <ryan.harkin@linaro.org> wrote:
>> On 5 April 2017 at 21:38, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>>> Replace the uncached memory mapping of the framebuffer with a write-
>>> combining one. This improves performance, and avoids issues with
>>> unaligned accesses and DC ZVA instructions performed by the accelerated
>>> memcpy/memset routines.
>>>
>>> Contributed-under: TianoCore Contribution Agreement 1.0
>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>
>> Well, ... PL111 isn't usually enabled for me. And if I enable it,
>> neither Foundation nor AEMv8 models boot with or without this patch.
>>
>> So it's no worse than before....
>>
>
> Not even foundation model? That is strange ...
>

The reason we created a config without PL111 was because Foundation
didn't originally have a PL111. And I wanted a single binary to run on
Foundation and AEMv8. But ARM added it to Foundation about a year ago
and I've never tried it.

I'm happy for you to submit the patch if it works for you.


>>
>>> ---
>>>  ArmPlatformPkg/ArmVExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/ArmPlatformPkg/ArmVExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c b/ArmPlatformPkg/ArmVExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
>>> index 2000c9bdf436..d18d6b3e1665 100644
>>> --- a/ArmPlatformPkg/ArmVExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
>>> +++ b/ArmPlatformPkg/ArmVExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
>>> @@ -192,7 +192,7 @@ LcdPlatformGetVram (
>>>      ASSERT_EFI_ERROR(Status);
>>>
>>>      // Mark the VRAM as un-cachable. The VRAM is inside the DRAM, which is cachable.
>>> -    Status = Cpu->SetMemoryAttributes(Cpu, *VramBaseAddress, *VramSize, EFI_MEMORY_UC);
>>> +    Status = Cpu->SetMemoryAttributes(Cpu, *VramBaseAddress, *VramSize, EFI_MEMORY_WC);
>>>      ASSERT_EFI_ERROR(Status);
>>>      if (EFI_ERROR(Status)) {
>>>        gBS->FreePool(VramBaseAddress);
>>> --
>>> 2.7.4
>>>
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