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Subject: Re: [PATCH v2 01/10] wifi: rtlwifi: Remove bogus and dangerous ASPM
 disable/enable code
From: Kalle Valo <kvalo@kernel.org>
In-Reply-To: <20231124084725.12738-2-ilpo.jarvinen@linux.intel.com>
References: <20231124084725.12738-2-ilpo.jarvinen@linux.intel.com>
To: =?utf-8?q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Cc: "John W. Linville" <linville@tuxdriver.com>,
 Larry Finger <Larry.Finger@lwfinger.net>, linux-wireless@vger.kernel.org,
 Ping-Ke Shih <pkshih@realtek.com>, Bjorn Helgaas <bhelgaas@google.com>,
 linux-kernel@vger.kernel.org,
 =?utf-8?q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>,
 Bjorn Helgaas <bhelgaas@kernel.org>, stable@vger.kernel.org
User-Agent: pwcli/0.1.1-git (https://github.com/kvalo/pwcli/) Python/3.11.2
Message-ID: <170143450482.2072551.1616110971687036096.kvalo@kernel.org>
Date: Fri,  1 Dec 2023 12:41:46 +0000 (UTC)

Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> wrote:

> Ever since introduction in the commit 0c8173385e54 ("rtl8192ce: Add new
> driver") the rtlwifi code has, according to comments, attempted to
> disable/enable ASPM of the upstream bridge by writing into its LNKCTL
> register. However, the code has never been correct because it performs
> the writes to the device instead of the upstream bridge.
> 
> Worse yet, the offset where the PCIe capabilities reside is derived
> from the offset of the upstream bridge. As a result, the write will use
> an offset on the device that does not relate to the LNKCTL register
> making the ASPM disable/enable code outright dangerous.
> 
> Because of those problems, there is no indication that the driver needs
> disable/enable ASPM on the upstream bridge. As the Capabilities offset
> is not correctly calculated for the write to target device's LNKCTL
> register, the code is not disabling/enabling device's ASPM either.
> Therefore, just remove the upstream bridge related ASPM disable/enable
> code entirely.
> 
> The upstream bridge related ASPM code was the only user of the struct
> mp_adapter members num4bytes, pcibridge_pciehdr_offset, and
> pcibridge_linkctrlreg so those are removed as well.
> 
> Note: This change does not remove the code related to changing the
> device's ASPM on purpose (which is independent of this flawed code
> related to upstream bridge's ASPM).
> 
> Suggested-by: Bjorn Helgaas <bhelgaas@kernel.org>
> Fixes: 0c8173385e54 ("rtl8192ce: Add new driver")
> Fixes: 886e14b65a8f ("rtlwifi: Eliminate raw reads and writes from PCIe portion")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

10 patches applied to wireless-next.git, thanks.

b3943b3c2971 wifi: rtlwifi: Remove bogus and dangerous ASPM disable/enable code
5894d0089cbc wifi: rtlwifi: Convert LNKCTL change to PCIe cap RMW accessors
a4fcac11a25a wifi: rtlwifi: Convert to use PCIe capability accessors
6e071ae899f1 wifi: rtlwifi: rtl8821ae: Remove unnecessary PME_Status bit set
760bfed91201 wifi: rtlwifi: rtl8821ae: Reverse PM Capability exists check
9dcc75e0b7d0 wifi: rtlwifi: rtl8821ae: Use pci_find_capability()
7bd350d2ac91 wifi: rtlwifi: rtl8821ae: Add pdev into _rtl8821ae_clear_pci_pme_status()
05b311a3f915 wifi: rtlwifi: rtl8821ae: Access full PMCS reg and use pci_regs.h
217fbc032eaa wifi: rtlwifi: Remove unused PCI related defines and struct
874a0eda000d wifi: rtlwifi: Remove bridge vendor/device ids

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20231124084725.12738-2-ilpo.jarvinen@linux.intel.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches