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Commit 96941026a51e9cb8c2d2be7499301b7fcd9ee225

Authored by mark gross
Committed by Linus Torvalds
1 parent 6760da0197
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[PATCH] EDAC Coexistence with BIOS 

Address the issue of EDAC/BIOS coexistence for the e752x chip-sets.

We have found a problem where the BIOS will start the system with the error
registers (dev0:fun1) hidden and assuming it has exclusive access to them.
The edac driver violates this assumption.

The workaround this patch offers is to honor the hidden-ness as an
indication that it is not safe to use those registers.

Signed-off-by: Mark Gross <mark.gross@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 1 changed file with 16 additions and 1 deletions Side-by-side Diff

drivers/edac/e752x_edac.c
Diff comments   View file @ 9694102
... ... @@ -25,6 +25,8 @@
25 25 #include <linux/slab.h>
26 26 #include "edac_mc.h"
27 27  
  28 +static int force_function_unhide;
  29 +
28 30 #define e752x_printk(level, fmt, arg...) \
29 31 edac_printk(level, "e752x", fmt, ##arg)
30 32  
31 33  
... ... @@ -782,8 +784,16 @@
782 784 debugf0("%s(): mci\n", __func__);
783 785 debugf0("Starting Probe1\n");
784 786  
785   - /* enable device 0 function 1 */
  787 + /* check to see if device 0 function 1 is enabled; if it isn't, we
  788 + * assume the BIOS has reserved it for a reason and is expecting
  789 + * exclusive access, we take care not to violate that assumption and
  790 + * fail the probe. */
786 791 pci_read_config_byte(pdev, E752X_DEVPRES1, &stat8);
  792 + if (!force_function_unhide && !(stat8 & (1 << 5))) {
  793 + printk(KERN_INFO "Contact your BIOS vendor to see if the "
  794 + "E752x error registers can be safely un-hidden\n");
  795 + goto fail;
  796 + }
787 797 stat8 |= (1 << 5);
788 798 pci_write_config_byte(pdev, E752X_DEVPRES1, stat8);
789 799  
... ... @@ -1063,4 +1073,8 @@
1063 1073 MODULE_LICENSE("GPL");
1064 1074 MODULE_AUTHOR("Linux Networx (http://lnxi.com) Tom Zimmerman\n");
1065 1075 MODULE_DESCRIPTION("MC support for Intel e752x memory controllers");
  1076 +
  1077 +module_param(force_function_unhide, int, 0444);
  1078 +MODULE_PARM_DESC(force_function_unhide, "if BIOS sets Dev0:Fun1 up as hidden:"
  1079 +" 1=force unhide and hope BIOS doesn't fight driver for Dev0:Fun1 access");