From: Sudeep Holla <sudeep.holla@arm.com>
To: Peter Collingbourne <pcc@google.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Will Deacon <will@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Sudeep Holla <sudeep.holla@arm.com>
Subject: Re: [PATCH] arm64: dts: fast models: Switch to dynamically allocated VRAM
Date: Fri, 24 Apr 2020 14:20:56 +0100 [thread overview]
Message-ID: <20200424132056.GA6544@bogus> (raw)
In-Reply-To: <20200423234903.226369-1-pcc@google.com>
On Thu, Apr 23, 2020 at 04:49:03PM -0700, Peter Collingbourne wrote:
> According to the Fast Models Reference Manual, FVP has 32MB of video
> RAM, However, even 32MB is not sufficient for some applications,
> such as Android, which requires around 100-200MB when textures are
> allocated in VRAM via DRM.
>
> FVP supports DMA between DRAM and the graphics device. Therefore,
> use a dynamically allocated region of reserved memory to provide
> a sufficient amount of video RAM. The allocation is of size 256MB,
> which ought to be enough for anyone.
>
> Although this means that the designated VRAM ends up being left unused,
> FVP allows the size of DRAM to be configurable, so this should not
> be a problem in practice.
>
> Signed-off-by: Peter Collingbourne <pcc@google.com>
> ---
> arch/arm64/boot/dts/arm/fvp-base-revc.dts | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/arm/fvp-base-revc.dts b/arch/arm64/boot/dts/arm/fvp-base-revc.dts
> index 66381d89c1ce..57641f16f22e 100644
> --- a/arch/arm64/boot/dts/arm/fvp-base-revc.dts
> +++ b/arch/arm64/boot/dts/arm/fvp-base-revc.dts
> @@ -103,11 +103,9 @@ reserved-memory {
> #size-cells = <2>;
> ranges;
>
> - /* Chipselect 2,00000000 is physically at 0x18000000 */
> - vram: vram@18000000 {
> - /* 8 MB of designated video RAM */
> + vram: vram {
> compatible = "shared-dma-pool";
> - reg = <0x00000000 0x18000000 0 0x00800000>;
I am not sure if it is valid to just specify the size without the reg
field. The reverse is valid IIUC. Moreover I assume the idea is to populate
the reg field based on the model parameters ? If so, who can't the reg
and size field be modified instead of deleting here and adding it elsewhere.
--
Regards,
Sudeep
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next prev parent reply other threads:[~2020-04-24 13:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 23:14 [PATCH] arm64: dts: fast models: Fix FVP video RAM size Peter Collingbourne
2020-04-23 23:30 ` Peter Collingbourne
2020-04-23 23:49 ` [PATCH] arm64: dts: fast models: Switch to dynamically allocated VRAM Peter Collingbourne
2020-04-24 13:20 ` Sudeep Holla [this message]
2020-04-28 13:06 ` [PATCH] arm64: dts: fast models: Fix FVP video RAM size Linus Walleij
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