1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 12c88c588039..cfa9ed179d9c 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -832,6 +832,21 @@ void ata_bmdma_post_internal_cmd(struct ata_queued_cmd *qc)
 }
 
 #ifdef CONFIG_PCI
+
+static int ata_resources_present(struct pci_dev *pdev, int port)
+{
+        int i;
+        
+        /* Check the PCI resources for this channel are enabled */
+        port = port * 2;
+        for (i = 0; i < 2; i ++) {
+                if (pci_resource_start(pdev, port + i) == 0 ||
+                        pci_resource_len(pdev, port + i) == 0)
+                return 0;
+        }
+        return 1;
+}
+                
 /**
  *      ata_pci_init_native_mode - Initialize native-mode driver
  *      @pdev:  pci device to be initialized
@@ -863,6 +878,13 @@ ata_pci_init_native_mode(struct pci_dev *pdev, struct ata_port_info **port, int
 
         probe_ent->irq = pdev->irq;
         probe_ent->irq_flags = IRQF_SHARED;
+        
+        /* Discard disabled ports. Some controllers show their
+           unused channels this way */
+        if (ata_resources_present(pdev, 0) == 0)
+                ports &= ~ATA_PORT_PRIMARY;
+        if (ata_resources_present(pdev, 1) == 0)
+                ports &= ~ATA_PORT_SECONDARY;
 
         if (ports & ATA_PORT_PRIMARY) {
                 probe_ent->port[p].cmd_addr = pci_resource_start(pdev, 0);