From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 EF4A9563288; Wed, 14 Oct 2026 16:58:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791997112; cv=none; b=MyZ8Av1SsuTGS1eRE507Ff6OtnQb8vFu8gqTvFeuZa5UDT7RBdZyL2mWGj+oQZ0tJ3XYP6evpJush+PPcE1GhAYC3uTLjIjHLue/TPsZJ8NDipgVyIlQfkcPbo6VOZuuIqwZ81+1UiwpY/WYO6N37CFIPHJSIzHTPCX2fr6aKk0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791997112; c=relaxed/simple; bh=SWMfrCIO4YtH5M5e+HBbAjTtGT/8z2eh56CZQAT9lsQ=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=AAKrpP03MAAMtxfwFttEljEVUHmaeX/gqtWE9a5prlnILYqMUVJ7OCieFylOmOXY/U9VDCyanvO/8ihMHxE75r4NYb/U4l7rHDdN1sXhZu71CK0gaEZrsOEuXAa7RQJpL2ystvnNgV0cIPK1byMB8WT18t/9l+oysp30yHulBR8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=a6ri6WzS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="a6ri6WzS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D5721F000C4; Wed, 14 Oct 2026 16:58:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791997110; bh=pC10JpWaZK5q2nplJQQ/7Ng9MIH1WaCTPiIEoz3L6+4=; h=Date:From:To:Cc:Subject:In-Reply-To; b=a6ri6WzS7o+KWbVhLNAerubNn8eACMbiby8b3bioPlA4QdWHkcT/EIZTBMeZruyOz uFIDz8t6NrFuh5yk2shxhD7OT1DfrWP19ss8/TBCBNVCaQj+pCvW3494pdTaAvuUdB W4FyN9YXYOlr5UInPQ5d4cf8+sFaXMJlnSYGfHPzNIg7PnGm5FBsZYSxoi0Z2jGpwf z7j2twiYiukHuc5EnkNzB9fsY7g1qECKtF6Fc2CJAOfCm/4xRrXTCmZhBfEGyjG2r7 g8FGdd9RuTqcqb8sHYSW3kEXBRv4RLmwxnCpTz3W7ekkgUVuxDHfFHf6P9vsYTuZmn S8oAqGYUm2bEQ== Date: Wed, 14 Oct 2026 11:58:29 -0500 From: Bjorn Helgaas To: Jose Ignacio Tornos Martinez Cc: bhelgaas@google.com, alex@shazbot.org, jjohnson@kernel.org, johannes@sipsolutions.net, mani@kernel.org, jgg@ziepe.ca, yishaih@nvidia.com, skolothumtho@nvidia.com, kevin.tian@intel.com, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-wireless@vger.kernel.org, ath11k@lists.infradead.org, ath12k@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/7] ath11k: add PCIe link recovery retry Message-ID: <20261014165829.GA1636877@bhelgaas> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260930140833.576941-5-jtornosm@redhat.com> On Wed, Sep 30, 2026 at 04:08:30PM +0200, Jose Ignacio Tornos Martinez wrote: > When ath11k devices are passed through to VMs via PCIe passthrough, > the PCIe link may not stabilize immediately after global reset due to > virtualization layer timing variations. This causes MHI initialization > to fail with "BHI offset: 0xffffffff is out of range" errors because > the device is read before it's ready. > > Currently, ath11k_pci_soc_global_reset() just warns if the link is > down but continues anyway, leading to inevitable MHI failures. > > This patch adds: > 1. A retry loop (up to 5000ms) to wait for the PCIe link to recover > after global reset (similar to the existing ath12k LTSSM retry logic) > 2. Proper error propagation to prevent continuing with a dead link > > This is especially important for VM environments where timing can vary > significantly from bare metal. > > Signed-off-by: Jose Ignacio Tornos Martinez > --- > drivers/net/wireless/ath/ath11k/pci.c | 39 ++++++++++++++++++++++----- > 1 file changed, 32 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/wireless/ath/ath11k/pci.c b/drivers/net/wireless/ath/ath11k/pci.c > index 7114eca8810d..4fc6aaf036c1 100644 > --- a/drivers/net/wireless/ath/ath11k/pci.c > +++ b/drivers/net/wireless/ath/ath11k/pci.c > @@ -190,8 +190,10 @@ static void ath11k_pci_restore_window(struct ath11k_base *ab) > spin_unlock_bh(&ab_pci->window_lock); > } > > -static void ath11k_pci_soc_global_reset(struct ath11k_base *ab) > +static int ath11k_pci_soc_global_reset(struct ath11k_base *ab) > { > + unsigned long timeout; > + bool link_recovered = false; > u32 val, delay; > > val = ath11k_pcic_read32(ab, PCIE_SOC_GLOBAL_RESET); > @@ -211,14 +213,29 @@ static void ath11k_pci_soc_global_reset(struct ath11k_base *ab) > > mdelay(delay); > > - val = ath11k_pcic_read32(ab, PCIE_SOC_GLOBAL_RESET); > - if (val == 0xffffffff) > - ath11k_warn(ab, "link down error during global reset\n"); > + /* Wait for PCIe link to recover, especially important in VM environments > + * where timing can vary significantly from bare metal. > + */ > + timeout = jiffies + msecs_to_jiffies(5000); > + while (time_before(jiffies, timeout)) { > + val = ath11k_pcic_read32(ab, PCIE_SOC_GLOBAL_RESET); > + if (val != 0xffffffff) { > + link_recovered = true; > + break; > + } > + mdelay(20); > + } > + if (!link_recovered) { > + ath11k_err(ab, "PCIe link failed to recover - device may need power cycle\n"); > + return -ETIMEDOUT; > + } Link down is a PCIe reset of the endpoint, which should clear all PCIe-specific state, e.g., BAR values. Is that restored somewhere? > /* Restore window register as its content is cleared during > * hardware global reset, such that it aligns with host cache. > */ > ath11k_pci_restore_window(ab); > + > + return 0; > } > > static void ath11k_pci_clear_dbg_registers(struct ath11k_base *ab) > @@ -373,8 +390,10 @@ static void ath11k_pci_force_wake(struct ath11k_base *ab) > mdelay(5); > } > > -static void ath11k_pci_sw_reset(struct ath11k_base *ab, bool power_on) > +static int ath11k_pci_sw_reset(struct ath11k_base *ab, bool power_on) > { > + int ret; > + > mdelay(100); > > if (power_on) { > @@ -387,8 +406,12 @@ static void ath11k_pci_sw_reset(struct ath11k_base *ab, bool power_on) > > ath11k_mhi_clear_vector(ab); > ath11k_pci_clear_dbg_registers(ab); > - ath11k_pci_soc_global_reset(ab); > + ret = ath11k_pci_soc_global_reset(ab); > + if (ret) > + return ret; > ath11k_mhi_set_mhictrl_reset(ab); > + > + return 0; > } > > static void ath11k_pci_init_qmi_ce_config(struct ath11k_base *ab) > @@ -818,7 +841,9 @@ static int ath11k_pci_power_up(struct ath11k_base *ab) > > ab_pci->register_window = 0; > clear_bit(ATH11K_FLAG_DEVICE_INIT_DONE, &ab->dev_flags); > - ath11k_pci_sw_reset(ab_pci->ab, true); > + ret = ath11k_pci_sw_reset(ab_pci->ab, true); > + if (ret) > + return ret; > > /* Disable ASPM during firmware download due to problems switching > * to AMSS state. > -- > 2.53.0 >