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scsi: megaraid_sas: Increase register read retry rount from 3 to 30 for selected registers 

In BMC environments with concurrent access to multiple registers, certain
registers occasionally yield a value of 0 even after 3 retries due to
hardware errata. As a fix, we have extended the retry count from 3 to 30.

The same errata applies to the mpt3sas driver, and a similar patch has
been accepted. Please find more details in the mpt3sas patch reference
link.

Link: https://lore.kernel.org/r/20230829090020.5417-2-ranjan.kumar@broadcom.com
Fixes: 272652fcbf ("scsi: megaraid_sas: add retry logic in megasas_readl")
Cc: stable@vger.kernel.org
Signed-off-by: Chandrakanth patil <chandrakanth.patil@broadcom.com>
Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
Link: https://lore.kernel.org/r/20231003110021.168862-2-chandrakanth.patil@broadcom.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Chandrakanth patil 2023-10-03 16:30:18 +05:30 committed by Martin K. Petersen
parent 0bb80ecc33
commit 8e3ed9e786
1 changed files with 2 additions and 2 deletions
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4
drivers/scsi/megaraid/megaraid_sas_base.c
View File

@ -263,13 +263,13 @@ u32 megasas_readl(struct megasas_instance *instance,
* Fusion registers could intermittently return all zeroes.
* This behavior is transient in nature and subsequent reads will
* return valid value. As a workaround in driver, retry readl for
* upto three times until a non-zero value is read.
* up to thirty times until a non-zero value is read.
*/
if (instance->adapter_type == AERO_SERIES) {
do {
ret_val = readl(addr);
i++;
} while (ret_val == 0 && i < 3);
} while (ret_val == 0 && i < 30);
return ret_val;
} else {
return readl(addr);