linux-kernel - Re: [PATCH RESEND] wifi: mt76: mt7921e: Set memory space enable in PCI

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Message-ID: <CAGp9LzrkX4uFAtLwvjH+uUuRgT_YDg3eE8SqgWEXOFmw5r=aMQ@mail.gmail.com>
Date:   Wed, 29 Mar 2023 16:24:10 -0700
From:   Sean Wang <sean.wang@...nel.org>
To:     Mario Limonciello <mario.limonciello@....com>
Cc:     nbd@....name, lorenzo@...nel.org, ryder.lee@...iatek.com,
        shayne.chen@...iatek.com, sean.wang@...iatek.com,
        Matthias Brugger <matthias.bgg@...il.com>,
        Anson Tsao <anson.tsao@....com>, Kalle Valo <kvalo@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND] wifi: mt76: mt7921e: Set memory space enable in
 PCI_COMMAND if unset

Hi,

On Wed, Mar 29, 2023 at 1:18 PM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> When the BIOS has been configured for Fast Boot, systems with mt7921e
> have non-functional wifi.  Turning on Fast boot caused both bus master
> enable and memory space enable bits in PCI_COMMAND not to get configured.
>
> The mt7921 driver already sets bus master enable, but explicitly check
> and set memory access enable as well to fix this problem.
>
> Tested-by: Anson Tsao <anson.tsao@....com>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> Original patch was submitted ~3 weeks ago with no comments.
> Link: https://lore.kernel.org/all/20230310170002.200-1-mario.limonciello@amd.com/
> ---
>  drivers/net/wireless/mediatek/mt76/mt7921/pci.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/pci.c b/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
> index cb72ded37256..aa1a427b16c2 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
> @@ -263,6 +263,7 @@ static int mt7921_pci_probe(struct pci_dev *pdev,
>         struct mt76_dev *mdev;
>         u8 features;
>         int ret;
> +       u16 cmd;
>
>         ret = pcim_enable_device(pdev);
>         if (ret)
> @@ -272,6 +273,11 @@ static int mt7921_pci_probe(struct pci_dev *pdev,
>         if (ret)
>                 return ret;
>
> +       pci_read_config_word(pdev, PCI_COMMAND, &cmd);
> +       if (!(cmd & PCI_COMMAND_MEMORY)) {
> +               cmd |= PCI_COMMAND_MEMORY;
> +               pci_write_config_word(pdev, PCI_COMMAND, cmd);
> +       }

If PCI_COMMAND_MEMORY is required in any circumstance, then we don't
need to add a conditional check and OR it with PCI_COMMAND_MEMORY.
Also, I will try the patch on another Intel machine to see if it worked.

     Sean

>         pci_set_master(pdev);
>
>         ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
> --
> 2.34.1
>