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Petersen" , linux-scsi@vger.kernel.org, sathya.prakash@broadcom.com, sreekanth.reddy@broadcom.com, stable@vger.kernel.org Subject: Re: [PATCH v3 1/2] Perform additional retries if Doorbell read returns 0 From: "Martin K. 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PH0PR10MB4759.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Aug 2023 01:25:56.8366 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Yi8xK9TyGipvJTIsJXsH1zJPmERkWNLNAROsOUv9alRE+8zsIxJdTm8jz9OBEt62UBsB8h56EMZHzJKN2OEQKs9DXgSSrcv/yVMhVap1T/0= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR10MB4137 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-08-08_24,2023-08-08_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 malwarescore=0 spamscore=0 adultscore=0 mlxlogscore=697 bulkscore=0 phishscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2306200000 definitions=main-2308090011 X-Proofpoint-ORIG-GUID: bjiNgK19I9ZEF25hwYq433J1o0vyZ3hH X-Proofpoint-GUID: bjiNgK19I9ZEF25hwYq433J1o0vyZ3hH Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hi Ranjan, > But for few registers zero may be a valid value and we don=E2=80=99t want > those registers to get penalized with 30 read retries where 1/3 reads > would have sufficed. If 0 is a valid register value you'll end up always doing 3 retries before returning. Even if the first register reads were "successful". Peculiar! --=20 Martin K. Petersen Oracle Linux Engineering