[PATCH 15/17] scsi: arcmsr: Add driver module parameter msi_enable

[Ching Huang]

From: Ching Huang <ching2...@areca.com.tw>

Add module parameter msi_enable to has a chance to disable msi interrupt if 
between controller and system has
msi INT compatible issue.

Signed-off-by: Ching Huang <ching2...@areca.com.tw>
---

diff -uprN a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
--- a/drivers/scsi/arcmsr/arcmsr_hba.c  2017-12-05 11:44:36.000000000 +0800
+++ b/drivers/scsi/arcmsr/arcmsr_hba.c  2017-12-05 16:59:58.000000000 +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);
+MODULE_PARM_DESC(msi_enable, "Enable MSI interrupt(0 ~ 1), 
msi_enable=1(enable), =0(disable)");
+
 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 +835,17 @@ 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);
+                       if (nvec == 1) {
+                               dev_info(&pdev->dev, "msi enabled\n");
+                               goto msi_int1;
+                       }
+               }
+               nvec = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_LEGACY);
                if (nvec < 1)
                        return FAILED;
-
+msi_int1:
                flags = IRQF_SHARED;
        }