Messages in this thread | | | Date | Tue, 15 Nov 2011 09:10:54 +0100 | From | Niklas Söderlund <> | Subject | Re: [PATCH] amd64_edac: Fix K8 revD and later chip select sizes |
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On Mon 14 Nov 2011 05:54:59 PM CET, Borislav Petkov wrote: > > Fix DRAM chip select sizes calculation for K8, revisions D and E. > > Reported-by: Niklas Söderlund<niklas.soderlund@ericsson.com > Link: http://lkml.kernel.org/r/1320849178-23340-1-git-send-email-niklas.soderlund@ericsson.com > Signed-off-by: Borislav Petkov<borislav.petkov@amd.com> > --- > > @Niklas: would you please verify this patch fixes your issue? > > Thanks. > > drivers/edac/amd64_edac.c | 32 ++++++++++++++++++++++++++++---- > 1 files changed, 28 insertions(+), 4 deletions(-) > > diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c > index c9eee6d..6a83d49 100644 > --- a/drivers/edac/amd64_edac.c > +++ b/drivers/edac/amd64_edac.c > @@ -1132,12 +1132,36 @@ static int k8_dbam_to_chip_select(struct amd64_pvt *pvt, u8 dct, > return ddr2_cs_size(cs_mode, dclr& WIDTH_128); > } > else if (pvt->ext_model>= K8_REV_D) { > + unsigned diff; > WARN_ON(cs_mode> 10); > > - if (cs_mode == 3 || cs_mode == 8) > - return 32<< (cs_mode - 1); > - else > - return 32<< cs_mode; > + /* > + * the below calculation, besides trying to win an obfuscated C > + * contest, maps cs_mode values to DIMM chip select sizes. The > + * mappings are: > + * > + * cs_mode CS size (mb) > + * ======= ============ > + * 0 32 > + * 1 64 > + * 2 128 > + * 3 128 > + * 4 256 > + * 5 512 > + * 6 256 > + * 7 512 > + * 8 1024 > + * 9 1024 > + * 10 2048 > + * > + * Basically, it calculates a value with which to shift the > + * smallest CS size of 32MB. > + * > + * ddr[23]_cs_size have a similar purpose. > + */ > + diff = cs_mode/3 + (unsigned)(cs_mode> 5); > + > + return 32<< (cs_mode - diff); > } > else { > WARN_ON(cs_mode> 6);
Hi Borislav,
Yes the patch fixes my problem, but it truly is obfuscated C.
Thanks // Niklas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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