Hi,

On Tue, Jul 30, 2019 at 07:50:14PM +0800, yhchu...@realtek.com wrote:
> From: Yu-Yen Ting <stevent...@realtek.com>
> 
> MSI interrupt should be enabled on certain platform.
> 
> Add a module parameter disable_msi to disable MSI interrupt,
> driver will then use legacy interrupt instead.
> And the interrupt mode is not able to change at run-time, so
> the module parameter is read only.

Well, if we unbind/rebind the device, probe() will pick up the new
value. e.g.:

  echo '0000:01:00.0' > /sys/bus/pci/drivers/rtw_pci/unbind
  echo '0000:01:00.0' > /sys/bus/pci/drivers/rtw_pci/bind

So is it really necessary to mark read-only? I think there's a general
understanding that module parameters are not always "immediately
effective."

> Tested-by: Ján Veselý <jano.ves...@gmail.com>
> Signed-off-by: Yu-Yen Ting <stevent...@realtek.com>
> Signed-off-by: Yan-Hsuan Chuang <yhchu...@realtek.com>
> ---
>  drivers/net/wireless/realtek/rtw88/pci.c | 51 
> ++++++++++++++++++++++++++++++--
>  drivers/net/wireless/realtek/rtw88/pci.h |  1 +
>  2 files changed, 49 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtw88/pci.c 
> b/drivers/net/wireless/realtek/rtw88/pci.c
> index 23dd06a..25410f6 100644
> --- a/drivers/net/wireless/realtek/rtw88/pci.c
> +++ b/drivers/net/wireless/realtek/rtw88/pci.c
> @@ -10,6 +10,10 @@
>  #include "rx.h"
>  #include "debug.h"
>  
> +static bool rtw_disable_msi;
> +module_param_named(disable_msi, rtw_disable_msi, bool, 0444);
> +MODULE_PARM_DESC(disable_msi, "Set Y to disable MSI interrupt support");
> +
>  static u32 rtw_pci_tx_queue_idx_addr[] = {
>       [RTW_TX_QUEUE_BK]       = RTK_PCI_TXBD_IDX_BKQ,
>       [RTW_TX_QUEUE_BE]       = RTK_PCI_TXBD_IDX_BEQ,
> @@ -874,6 +878,7 @@ static irqreturn_t rtw_pci_interrupt_handler(int irq, 
> void *dev)
>       if (!rtwpci->irq_enabled)
>               goto out;
>  
> +     rtw_pci_disable_interrupt(rtwdev, rtwpci);

Why exactly do you have to mask interrupts during the ISR? Is there a
race in rtw_pci_irq_recognized() or something?

>       rtw_pci_irq_recognized(rtwdev, rtwpci, irq_status);
>  
>       if (irq_status[0] & IMR_MGNTDOK)

...

> @@ -1103,6 +1110,45 @@ static struct rtw_hci_ops rtw_pci_ops = {
>       .write_data_h2c = rtw_pci_write_data_h2c,
>  };
>  
> +static int rtw_pci_request_irq(struct rtw_dev *rtwdev, struct pci_dev *pdev)
> +{
> +     struct rtw_pci *rtwpci = (struct rtw_pci *)rtwdev->priv;
> +     int ret;
> +
> +     if (!rtw_disable_msi) {
> +             ret = pci_enable_msi(pdev);
> +             if (ret) {
> +                     rtw_warn(rtwdev, "failed to enable msi, using legacy 
> irq\n");
> +             } else {
> +                     rtw_warn(rtwdev, "pci msi enabled\n");
> +                     rtwpci->msi_enabled = true;
> +             }
> +     }
> +
> +     ret = request_irq(pdev->irq, &rtw_pci_interrupt_handler, IRQF_SHARED,
> +                       KBUILD_MODNAME, rtwdev);
> +     if (ret) {
> +             rtw_err(rtwdev, "failed to request irq\n");

Print out 'ret' here?

> +             if (rtwpci->msi_enabled) {
> +                     pci_disable_msi(pdev);
> +                     rtwpci->msi_enabled = false;
> +             }
> +     }
> +
> +     return ret;
> +}

Otherwise, looks fine:

Reviewed-by: Brian Norris <briannor...@chromium.org>

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