Re: [RFC PATCH v5 3/4] phy: rockchip-pcie: Enable all four lanes

From: Geraldo Nascimento <geraldogabriel@gmail.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: linux-rockchip@lists.infradead.org,
	"Shawn Lin" <shawn.lin@rock-chips.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Manivannan Sadhasivam" <mani@kernel.org>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Vinod Koul" <vkoul@kernel.org>,
	"Kishon Vijay Abraham I" <kishon@kernel.org>,
	"Rick wertenbroek" <rick.wertenbroek@gmail.com>,
	linux-phy@lists.infradead.org, linux-pci@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v5 3/4] phy: rockchip-pcie: Enable all four lanes
Date: Fri, 20 Jun 2025 09:50:01 -0300	[thread overview]
Message-ID: <aFVY-YtSTxUpJkIa@geday> (raw)
In-Reply-To: <aFVTdYWxuq9YzVQR@geday>

On Fri, Jun 20, 2025 at 09:26:36AM -0300, Geraldo Nascimento wrote:
> On Fri, Jun 20, 2025 at 01:04:46PM +0100, Robin Murphy wrote:
> > On 2025-06-13 6:03 pm, Geraldo Nascimento wrote:
> > > Current code enables only Lane 0 because pwr_cnt will be incremented
> > > on first call to the function. Use for-loop to enable all 4 lanes
> > > through GRF.
> > 
> > If this was really necessary, then surely it would also need the 
> > equivalent changes in rockchip_pcie_phy_power_off() too?
> > 
> > However, I'm not sure it *is* necessary - the NVMe on my RK3399 board 
> > happily claims to be using an x4 link, so I stuck a print of inst->index 
> > in this function, and sure enough I do see it being called for each 
> > instance already:
> > 
> > [    1.737479] phy phy-ff770000.syscon:pcie-phy.1: power_on 0
> > [    1.738810] phy phy-ff770000.syscon:pcie-phy.2: power_on 1
> > [    1.745193] phy phy-ff770000.syscon:pcie-phy.3: power_on 2
> > [    1.745196] phy phy-ff770000.syscon:pcie-phy.4: power_on 3
> > 
> 
> Hi Robin, and thanks for caring, it's excellent to rely on your
> extensive expertise on ARM in general and RK3399 specifically!
> 
> However, on my board I'm positive it does not work without proposed
> patch and I get stuck with x1 link without it.
> 
> There are currently very similar patches applied downstream to Armbian
> and OpenWRT so at least I'm confident that is not only my board which is
> quirky and other people experienced the same problem.
> 
> Thanks,
> Geraldo Nascimento

Hello again Robin,

for reference, here's the commit for OpenWRT, originally from Armbian:
https://github.com/openwrt/openwrt/commit/2dc9801fe81ab3c092d2ca75e4c63f8d5eea46f5

Please note that the author of that commit specifically mentions a warm
reboot is needed to trigger the "stuck on x1" behavior. That author took
a different strategy than me, just reordering instead of using for-loop.
I'm open for different strategies, but the report is real I assure you.

Geraldo Nascimento

> 
> > Thanks,
> > Robin.