Messages in this thread Patch in this message | | | Date | Fri, 08 Jun 2007 09:52:45 -0600 | From | dougthompson@xmission ... | Subject | [PATCH 2/6] |
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From: Jason Uhlenkott <juhlenko@akamai.com>
If ERRSTS indicates that there's no error then we don't need to bother reading the other registers.
In addition to making the common case faster, this actually fixes a small race where we don't see an error but we clear the error bits anyway, potentially wiping away info on an error that happened in the interim (or where a CE arrives between the first and second read of ERRSTS, causing us to falsely claim "UE overwrote CE").
Signed-off-by: Jason Uhlenkott <juhlenko@akamai.com> Signed-off-by: Douglas Thompson <dougthompson@xmission.com> Cc: alan@lxorguk.ukuu.org.uk --- i82875p_edac.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
--- linux.orig/drivers/edac/i82875p_edac.c 2007-05-21 00:46:31.568356390 -0400 +++ linux/drivers/edac/i82875p_edac.c 2007-05-21 00:46:36.637650484 -0400 @@ -198,27 +198,28 @@ * overwritten by UE. */ pci_read_config_word(pdev, I82875P_ERRSTS, &info->errsts); + + if (!(info->errsts & 0x0081)) + return; + pci_read_config_dword(pdev, I82875P_EAP, &info->eap); pci_read_config_byte(pdev, I82875P_DES, &info->des); pci_read_config_byte(pdev, I82875P_DERRSYN, &info->derrsyn); pci_read_config_word(pdev, I82875P_ERRSTS, &info->errsts2); - pci_write_bits16(pdev, I82875P_ERRSTS, 0x0081, 0x0081); - /* * If the error is the same then we can for both reads then * the first set of reads is valid. If there is a change then * there is a CE no info and the second set of reads is valid * and should be UE info. */ - if (!(info->errsts2 & 0x0081)) - return; - if ((info->errsts ^ info->errsts2) & 0x0081) { pci_read_config_dword(pdev, I82875P_EAP, &info->eap); pci_read_config_byte(pdev, I82875P_DES, &info->des); pci_read_config_byte(pdev, I82875P_DERRSYN, &info->derrsyn); } + + pci_write_bits16(pdev, I82875P_ERRSTS, 0x0081, 0x0081); } static int i82875p_process_error_info(struct mem_ctl_info *mci, @@ -229,7 +230,7 @@ multi_chan = mci->csrows[0].nr_channels - 1; - if (!(info->errsts2 & 0x0081)) + if (!(info->errsts & 0x0081)) return 0; if (!handle_errors) - 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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