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X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: sony.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Sep 2024 13:47:19.3944 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: dcca2898-51a9-4b6a-6b71-08dcdefae859 X-MS-Exchange-CrossTenant-Id: 66c65d8a-9158-4521-a2d8-664963db48e4 X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=66c65d8a-9158-4521-a2d8-664963db48e4;Ip=[121.100.38.198];Helo=[gepdcl09.sg.gdce.sony.com.sg] X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: TreatMessagesAsInternal-BN2PEPF000055DF.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA2PR13MB6703 X-Proofpoint-GUID: 1Kt2VX25IzvKHt0P7RqM_QegPkahuZhd X-Proofpoint-ORIG-GUID: 1Kt2VX25IzvKHt0P7RqM_QegPkahuZhd X-Sony-Outbound-GUID: 1Kt2VX25IzvKHt0P7RqM_QegPkahuZhd X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-27_06,2024-09-27_01,2024-09-02_01 Hi Greg, Sorry for the delay in our response. Please find our reply to your comments: On Tue, Sep 17, 2024 at 12:11:22PM +0200, Greg KH wrote: > > On Fri, Sep 13, 2024 at 06:36:38AM +0200, Greg KH wrote: > > > > This patch series introduces a new framework in the form of a driver > > > > probe-control, aimed at addressing the need for deferring the probes > > > > from built-in drivers in kernels where modules are not used. > > > > > > Wait, why? > > > > > > > We have a scenario where a driver cannot be built as a module and ends up > > as a built-in driver. We don't want to probe this driver during boot as its > > not required at the time of booting. > > Example: drivers/pci/controller/dwc/pci-imx6.c > > So the intention is to only postpone some driver probes similar to: > > https://elinux.org/Deferred_Initcalls > > But instead of delaying initcall execution(which requires initmem to be kept > > and not freed during boot) we are trying to delay driver probes as this is > > much simpler. > > The proposed driver is a generic solution for managing such driver > > probes. > > Again, please fix the drivers that are having problems with this, and > build them as a module and load them when you need/want them and can be > probed correctly. > Sure, we will try to do that. > > > > In such scenario, delaying the initialization of certain devices such > > > > as pcie based devices not needed during boot and giving user the control > > > > on probing these devices post boot, can help reduce overall boot time. > > > > This is achieved without modifying the driver code, simply by configuring > > > > the platform device tree. > > > > > > PCI devices should not be on the platform device tree. > > > > > > > You are right, we are referring to the pci host controller that will be > > listed in device tree and skipping its probe during boot as an example > > here. > > pci host controllers should really be availble at boot time, wow your > hardware is b0rked, sorry. Just make it a module and load it when you > want/need it. > > > > And what's wrong with async probing? That was written for this very > > > issue. > > > > > > > We have explored async probe as an option, but we noticed below: > > 1) Probe initiated via async > > 2) Boot continues with other setup. > > 3) Boot reaches stage where ip configuration is to be done via > > ip_auto_config() and 1) is still in progress, then boot waits for all > > async calls to be completed before proceeding with network setup. > > ip_auto_config() > > -> wait_for_devices() > > -> wait_for_device_probe() > > -> async_synchronize_full() > > 4) Similar thing happens with rootfs mount step in prepare_namespace() > > initcall > > Again, if you make the problem driver as a module you should be ok, > right? > Yes. > > So to avoid getting blocked on these probes which are not required > > during boot, we proposed this driver for managing such built-in driver > > probes execution. > > Fix the broken drivers please :) > Sure, we will do that. Thank you for your feedback. Regards, Nayeem