From: akarbown <>

In one of the previous patches we decreased NUM_CHANNELS from 8 to 4, but
it is not enough for Knights Landing which supports up to 6 channels.

This caused unattended writes to pvt->mirror_mode and pvt->tolm variables
which don't pay critical role on KNL code path, so driver was somehow 

The easiest way of fixing it is to change NUM_CHANNELS to 6.
An alternative solution would be to restructure KNL part of the driver to
2MC/3channel representation.

Fixes: 3286d3eb906c ("EDAC, sb_edac: Drop NUM_CHANNELS from 8 back to 4")
Reported-by: Dan Carpenter <>
Signed-off-by: Anna Karbownik <>
 drivers/edac/sb_edac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/edac/sb_edac.c b/drivers/edac/sb_edac.c
index f34430f..8721002 100644
--- a/drivers/edac/sb_edac.c
+++ b/drivers/edac/sb_edac.c
@@ -279,7 +279,7 @@ static inline int sad_pkg(const struct interleave_pkg 
*table, u32 reg,
  * sbridge structs
-#define NUM_CHANNELS           4       /* Max channels per MC */
+#define NUM_CHANNELS           6       /* Max channels per MC */
 #define MAX_DIMMS              3       /* Max DIMMS per channel */
 #define KNL_MAX_CHAS           38      /* KNL max num. of Cache Home Agents */
 #define KNL_MAX_CHANNELS       6       /* KNL max num. of PCI channels */


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