[PATCH] EDAC/amd64: Use maximum channel count for the EDAC channel layer size

[PATCH] EDAC/amd64: Use maximum channel count for the EDAC channel layer size

[Ghannam, Yazen]

From: Yazen Ghannam <yazen.ghannam@amd.com>

The AMD64 EDAC module current hardcodes the EDAC channel layer size
(count) to two. Future AMD systems may have more channels than this.

Set the EDAC channel layer size equal to the maximum number of channels
possible for the system. On Family 17h and later, this is set in the
num_umcs variable. Older systems will continue to use two as the
default.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
 drivers/edac/amd64_edac.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index b7617fad282c..4c0239aeff2f 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -3357,8 +3357,14 @@ static int init_one_instance(unsigned int nid)
 	 * Always allocate two channels since we can have setups with DIMMs on
 	 * only one channel. Also, this simplifies handling later for the price
 	 * of a couple of KBs tops.
+	 *
+	 * On Fam17h+, the number of controllers may be greater than two. So set
+	 * the size equal to the maximum number of UMCs.
 	 */
-	layers[1].size = 2;
+	if (pvt->fam >= 0x17)
+		layers[1].size = num_umcs;
+	else
+		layers[1].size = 2;
 	layers[1].is_virt_csrow = false;
 
 	mci = edac_mc_alloc(nid, ARRAY_SIZE(layers), layers, 0);
-- 
2.17.1

Re: [PATCH] EDAC/amd64: Use maximum channel count for the EDAC channel layer size

[Borislav Petkov]

On Mon, Mar 25, 2019 at 08:33:30PM +0000, Ghannam, Yazen wrote:
> From: Yazen Ghannam <yazen.ghannam@amd.com>
> 
> The AMD64 EDAC module current hardcodes the EDAC channel layer size
> (count) to two. Future AMD systems may have more channels than this.
> 
> Set the EDAC channel layer size equal to the maximum number of channels
> possible for the system. On Family 17h and later, this is set in the
> num_umcs variable. Older systems will continue to use two as the
> default.
> 
> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> ---
>  drivers/edac/amd64_edac.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)

Ok, whole pile here:

https://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git/log/?h=edac-for-5.2-amd64

Please run it to check all is still good.

Thx.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

RE: [PATCH] EDAC/amd64: Use maximum channel count for the EDAC channel layer size

[Ghannam, Yazen]

> -----Original Message-----
> From: Borislav Petkov <bp@alien8.de>
> Sent: Tuesday, March 26, 2019 10:55 AM
> To: Ghannam, Yazen <Yazen.Ghannam@amd.com>
> Cc: linux-edac@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] EDAC/amd64: Use maximum channel count for the EDAC channel layer size
> 
> On Mon, Mar 25, 2019 at 08:33:30PM +0000, Ghannam, Yazen wrote:
> > From: Yazen Ghannam <yazen.ghannam@amd.com>
> >
> > The AMD64 EDAC module current hardcodes the EDAC channel layer size
> > (count) to two. Future AMD systems may have more channels than this.
> >
> > Set the EDAC channel layer size equal to the maximum number of channels
> > possible for the system. On Family 17h and later, this is set in the
> > num_umcs variable. Older systems will continue to use two as the
> > default.
> >
> > Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> > ---
> >  drivers/edac/amd64_edac.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> Ok, whole pile here:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git/log/?h=edac-for-5.2-amd64
> 
> Please run it to check all is still good.
> 

Just tested on a fully populated system. Everything seems to be okay.

Thanks,
Yazen

Re: [PATCH] EDAC/amd64: Use maximum channel count for the EDAC channel layer size

[Borislav Petkov]

On Tue, Mar 26, 2019 at 07:15:29PM +0000, Ghannam, Yazen wrote:
> Just tested on a fully populated system. Everything seems to be okay.

Thanks, queued.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.