[PATCH 4.2 092/110] EDAC, sb_edac: Fix TAD presence check for sbridge_mci_bind_devs()

From: Greg Kroah-Hartman
Date: Fri Nov 06 2015 - 14:27:21 EST

4.2-stable review patch. If anyone has any objections, please let me know.


From: Seth Jennings <sjenning@xxxxxxxxxx>

commit 2900ea609616c2651dec65312beeb2a6e536bc50 upstream.

In commit

7d375bffa524 ("sb_edac: Fix support for systems with two home agents per socket")

NUM_CHANNELS was changed to 8 and the channel space was renumerated to
handle EN, EP, and EX configurations.

The *_mci_bind_devs() functions - except for sbridge_mci_bind_devs() -
got a new device presence check in the form of saw_chan_mask. However,
sbridge_mci_bind_devs() still uses the NUM_CHANNELS for loop.

With the increase in NUM_CHANNELS, this loop fails at index 4 since
SB only has 4 TADs. This results in the following error on SB machines:

EDAC sbridge: Some needed devices are missing
EDAC sbridge: Couldn't find mci handler
EDAC sbridge: Couldn't find mci handle

This patch adapts the saw_chan_mask logic for sbridge_mci_bind_devs() as

After this patch:

EDAC MC0: Giving out device to module sbridge_edac.c controller Sandy Bridge Socket#0: DEV 0000:3f:0e.0 (POLLED)
EDAC MC1: Giving out device to module sbridge_edac.c controller Sandy Bridge Socket#1: DEV 0000:7f:0e.0 (POLLED)

Signed-off-by: Seth Jennings <sjenning@xxxxxxxxxx>
Acked-by: Aristeu Rozanski <aris@xxxxxxxxxx>
Acked-by: Tony Luck <tony.luck@xxxxxxxxx>
Tested-by: Borislav Petkov <bp@xxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
Cc: linux-edac <linux-edac@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1438798561-10180-1-git-send-email-sjenning@xxxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/edac/sb_edac.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/edac/sb_edac.c
+++ b/drivers/edac/sb_edac.c
@@ -1648,6 +1648,7 @@ static int sbridge_mci_bind_devs(struct
struct sbridge_pvt *pvt = mci->pvt_info;
struct pci_dev *pdev;
+ u8 saw_chan_mask = 0;
int i;

for (i = 0; i < sbridge_dev->n_devs; i++) {
@@ -1681,6 +1682,7 @@ static int sbridge_mci_bind_devs(struct
int id = pdev->device - PCI_DEVICE_ID_INTEL_SBRIDGE_IMC_TAD0;
pvt->pci_tad[id] = pdev;
+ saw_chan_mask |= 1 << id;
@@ -1701,10 +1703,8 @@ static int sbridge_mci_bind_devs(struct
!pvt-> pci_tad || !pvt->pci_ras || !pvt->pci_ta)
goto enodev;

- for (i = 0; i < NUM_CHANNELS; i++) {
- if (!pvt->pci_tad[i])
- goto enodev;
- }
+ if (saw_chan_mask != 0x0f)
+ goto enodev;
return 0;


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