From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D232AFBF0 for ; Fri, 30 May 2025 15:21:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748618481; cv=none; b=trFVCtjL53ED3tf4uTEBZM/ec0gK9iIadpwcduZDZBPeK0kzJgk0nZ85VH49rOSLUW4ZDJr05oImwyGUOOnP0szQgDdQaH/unbY+Y1TuK96o1FEK6sFbe4HqOOH9Dmm3/qWN/PAs7M1WXl/QHqzaFvwi8Pxh3640veD4zcQpmPY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748618481; c=relaxed/simple; bh=SiP/PmZazfxbyJmRDRcM0CTDd+dhG9xAFjjnfdmUn1E=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=ZUXjZvjcSzNHxSWkPphxoYvxZ93Tmxk9dzqw+8ZypEJvC8YrX5v45HjJPe1UyOMy6qXswgoEx4G0FiUeBeAlf8dk0d9Gb2QNR/DtNkC/HH5H8raErSKkXlX9M9zB1QE/+PzDiD1S/46/w+MOXlvyIh9Og+EgMdvRjUGGWA/KDTg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NKMX6Jkr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NKMX6Jkr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E92AC4CEE9; Fri, 30 May 2025 15:21:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1748618480; bh=SiP/PmZazfxbyJmRDRcM0CTDd+dhG9xAFjjnfdmUn1E=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=NKMX6JkrU2+697Aud1vEUya2Txa/Mtx2yEuVUIqz00k2pKaoJ5MPParaRNRA/kXYq 225g0OLhRuY6dVEuEgC26AqVSignocKK57h74d1dXlKIi8nbapJe7x3BjwZ0Nq4nYl HoOWRCmCS29vkWU+X4pqJQRft5iTCevVaJc6OU29A/GW6oo4atgFO0bJfSOgYoMTo9 XazzNP+0pMzT5hQZS56J/uyPib105RaFXoZgkhODAsrooWOedQWHGm6zEQqHrHOxxI aHUJiFOZMaeCJoGHU2u6mJQnC2UFpItTnCpBsM4KtbzFAbkTLDpGoS/ulxgz0hBPGR 41cJ1N4Z5tDFg== Date: Fri, 30 May 2025 10:21:18 -0500 From: Bjorn Helgaas To: Niklas Cassel Cc: Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Manivannan Sadhasivam , Rob Herring , Bjorn Helgaas , Heiko Stuebner , Wilfred Mallawa , Damien Le Moal , Hans Zhang <18255117159@163.com>, Laszlo Fiat , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH v2 1/4] PCI: dw-rockchip: Do not enumerate bus before endpoint devices are ready Message-ID: <20250530152118.GA148072@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, May 30, 2025 at 03:57:14PM +0200, Niklas Cassel wrote: > On Wed, May 28, 2025 at 05:42:51PM -0500, Bjorn Helgaas wrote: > > On Tue, May 06, 2025 at 09:39:36AM +0200, Niklas Cassel wrote: > > > Commit ec9fd499b9c6 ("PCI: dw-rockchip: Don't wait for link since we can > > > detect Link Up") changed so that we no longer call dw_pcie_wait_for_link(), > > > and instead enumerate the bus when receiving a Link Up IRQ. > > > > > > Laszlo Fiat reported (off-list) that his PLEXTOR PX-256M8PeGN NVMe SSD is > > > no longer functional, and simply reverting commit ec9fd499b9c6 ("PCI: > > > dw-rockchip: Don't wait for link since we can detect Link Up") makes his > > > SSD functional again. > > > > > > It seems that we are enumerating the bus before the endpoint is ready. > > > Adding a msleep(PCIE_T_RRS_READY_MS) before enumerating the bus in the > > > threaded IRQ handler makes the SSD functional once again. > > > > This sounds like a problem that could happen with any controller, not > > just dw-rockchip? > > Correct. > > > Are we missing some required delay that should be > > in generic code? Or is this a PLEXTOR defect that everybody has to > > pay the price for? > > So far, the Plextor drive is the only endpoint that we know of, which is > not working without the delay. > > We have no idea if this Plextor drive is the only bad behaving endpoint or > if there are many endpoints with similar issues, because before the > use_linkup_irq() callback was introduced, we always had (the equivalent of) > this delay. > > Since this will only delay once the link up IRQ is triggered, it will not > affect the boot time when there are no endpoint plugged in to the slot, so > it seemed quite harmless to reintroduce this delay before enumeration. > > But other suggestions are of course welcome. > > > Since it seems that we can read the PCI vendor and PCI device ID, it seems > that at least some config space reads seem to work, so I guess that we could > try to quirk the PCI vendor and PCI device ID in the nvme driver. > > The nvme driver does have a NVME_QUIRK_DELAY_BEFORE_CHK_RDY quirk for some > Samsung drive, perhaps we could try something similar to the Plextor drive? Looks like NVME_QUIRK_DELAY_BEFORE_CHK_RDY is used for Seagate (Vendor ID 0x1bb1), Samsung (0x144d), Memblaze (0x1c5f), and HGST/WDC (0x1c58, annoyingly not shown as reserved by https://pcisig.com/membership/member-companies?combine=1c58) adapters. If we can read the Vendor and Device IDs (and, I assume, BARs and other things used by enumeration), it sounds like possibly an NVMe issue, not a PCI issue. If we can use NVME_QUIRK_DELAY_BEFORE_CHK_RDY for this drive as well, I think we should because it at least connects the extra delay with a specific device. > I don't personally have this problematic NVMe drive, so I am not able to test > such a patch. The user who reported the problem, Laszlo, has been doing all > the testing. > > > Perhaps Laszlo could try something like: > > > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c > index 6b04473c0ab7..9c409af34548 100644 > --- a/drivers/nvme/host/core.c > +++ b/drivers/nvme/host/core.c > @@ -2865,6 +2865,12 @@ static const struct nvme_core_quirk_entry core_quirks[] = { > .quirks = NVME_QUIRK_DELAY_BEFORE_CHK_RDY | > NVME_QUIRK_NO_DEEPEST_PS | > NVME_QUIRK_IGNORE_DEV_SUBNQN, > + }, > + { > + > + .vid = 0x144d, > + .mn = "Samsung Portable SSD X5", > + .quirks = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, > } > }; > > > .. with the .vid and .mn fields replacd with the correct ones for the Plextor > drive. (Don't forget to revert patch in $subject when testing this alternate > solution.) > > I don't have a preference for either solution. > > > Kind regards, > Niklas