Re: [PATCH 1/3] scsi: arcmsr: Add driver module parameter msi_enable

From: Dan Carpenter
Date: Thu Nov 23 2017 - 05:45:12 EST


On Thu, Nov 23, 2017 at 09:27:19AM +0800, Ching Huang wrote:
> From: Ching Huang <ching2048@xxxxxxxxxxxx>
>
> Add module parameter msi_enable to has a chance to disable msi interrupt if it does not work properly.
>
> Signed-off-by: Ching Huang <ching2048@xxxxxxxxxxxx>
> ---
>
> diff -uprN a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
> --- a/drivers/scsi/arcmsr/arcmsr_hba.c 2017-11-23 14:29:26.000000000 +0800
> +++ b/drivers/scsi/arcmsr/arcmsr_hba.c 2017-11-23 16:02:28.000000000 +0800
> @@ -75,6 +75,10 @@ MODULE_DESCRIPTION("Areca ARC11xx/12xx/1
> MODULE_LICENSE("Dual BSD/GPL");
> MODULE_VERSION(ARCMSR_DRIVER_VERSION);
>
> +static int msi_enable = 1;
> +module_param(msi_enable, int, S_IRUGO);
^^^^^^^
checkpatch.pl will complain that this should be 0444

> +MODULE_PARM_DESC(msi_enable, " Enable MSI interrupt(0 ~ 1), msi_enable=1(enable), =0(disable)");
^
Remove the extra space

> +
> static int host_can_queue = ARCMSR_DEFAULT_OUTSTANDING_CMD;
> module_param(host_can_queue, int, S_IRUGO);
> MODULE_PARM_DESC(host_can_queue, " adapter queue depth(32 ~ 1024), default is 128");
> @@ -831,11 +835,15 @@ arcmsr_request_irq(struct pci_dev *pdev,
> pr_info("arcmsr%d: msi-x enabled\n", acb->host->host_no);
> flags = 0;
> } else {
> - nvec = pci_alloc_irq_vectors(pdev, 1, 1,
> - PCI_IRQ_MSI | PCI_IRQ_LEGACY);
> + if (msi_enable == 1)
> + nvec = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
> + else
> + nvec = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_LEGACY);
> if (nvec < 1)
> return FAILED;

I feel like we should try PCI_IRQ_MSI then if it fails we could fall
back to PCI_IRQ_LEGACY. Originally, it worked like this and now it just
fails unless you toggle the module param. It's a regression.

>
> + if (msi_enable == 1)
> + pr_info("arcmsr%d: msi enabled\n", acb->host->host_no);

This printk could be improved. Use dev_info(&pdev->dev, for a start.
I know that the other prints don't use this, but we could use it one
time then slowly add more users until more are using dev_info() than
pr_info() and then someone will decide to clean up the old users.

regards,
dan carpenter