[PATCH 6 of 6] x86, UV: correct UV2 BAU destination timeout

[PATCH 6 of 6] x86, UV: correct UV2 BAU destination timeout

[Cliff Wickman]

From: Cliff Wickman <cpw@sgi.com>

Correct the UV2 broacast assist unit's destination timeout period.
  The period is set in 4 bits of memory-mapped register MISC_CONTROL.
  The left bit toggles base period between 10us and 80us.
  The other 3 bits are the multiplier.
Decimal 15, hex f, gives the maximum: 7 * 80us

And the activation status register in UV2 should be tested for a destination
timeout with a 4, not a 2.  The values for Active versus Timeout were reversed.

Diffed against 3.0.0-rc3
Signed-off-by: Cliff Wickman <cpw@sgi.com>

---
 arch/x86/include/asm/uv/uv_bau.h |   18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Index: linux/arch/x86/include/asm/uv/uv_bau.h
===================================================================
--- linux.orig/arch/x86/include/asm/uv/uv_bau.h
+++ linux/arch/x86/include/asm/uv/uv_bau.h
@@ -67,7 +67,7 @@
  *  we're using 655us, similar to UV1: 65 units of 10us
  */
 #define UV1_INTD_SOFT_ACK_TIMEOUT_PERIOD (9UL)
-#define UV2_INTD_SOFT_ACK_TIMEOUT_PERIOD (65*10UL)
+#define UV2_INTD_SOFT_ACK_TIMEOUT_PERIOD (15UL)
 
 #define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD	(is_uv1_hub() ?			\
 		UV1_INTD_SOFT_ACK_TIMEOUT_PERIOD :			\
@@ -106,12 +106,20 @@
 #define DS_SOURCE_TIMEOUT		3
 /*
  * bits put together from HRP_LB_BAU_SB_ACTIVATION_STATUS_0/1/2
- * values 1 and 5 will not occur
+ * values 1 and 3 will not occur
+ *        Decoded meaning              ERROR  BUSY    AUX ERR
+ * -------------------------------     ----   -----   -------
+ * IDLE                                 0       0        0
+ * BUSY (active)                        0       1        0
+ * SW Ack Timeout (destination)         1       0        0
+ * SW Ack INTD rejected (strong NACK)   1       0        1
+ * Source Side Time Out Detected        1       1        0
+ * Destination Side PUT Failed          1       1        1
  */
 #define UV2H_DESC_IDLE			0
-#define UV2H_DESC_DEST_TIMEOUT		2
-#define UV2H_DESC_DEST_STRONG_NACK	3
-#define UV2H_DESC_BUSY			4
+#define UV2H_DESC_BUSY			2
+#define UV2H_DESC_DEST_TIMEOUT		4
+#define UV2H_DESC_DEST_STRONG_NACK	5
 #define UV2H_DESC_SOURCE_TIMEOUT	6
 #define UV2H_DESC_DEST_PUT_ERR		7
 

Re: [PATCH 6 of 6] x86, UV: correct UV2 BAU destination timeout

[Ingo Molnar]

* Cliff Wickman <cpw@sgi.com> wrote:

> From: Cliff Wickman <cpw@sgi.com>
> 
> Correct the UV2 broacast assist unit's destination timeout period.
>   The period is set in 4 bits of memory-mapped register MISC_CONTROL.
>   The left bit toggles base period between 10us and 80us.
>   The other 3 bits are the multiplier.
> Decimal 15, hex f, gives the maximum: 7 * 80us
> 
> And the activation status register in UV2 should be tested for a destination
> timeout with a 4, not a 2.  The values for Active versus Timeout were reversed.

This changelog tells us everything except what a user of this code 
would be most interested in: what was the practical effect of the 
bug, how badly does the user want the fix?

Thanks,

	Ingo