{"id":659,"date":"2015-11-27T13:15:20","date_gmt":"2015-11-27T04:15:20","guid":{"rendered":"http:\/\/naraeon.net\/?p=659"},"modified":"2024-09-24T22:43:38","modified_gmt":"2024-09-24T13:43:38","slug":"pci-express-linkwidth-linkspeed","status":"publish","type":"post","link":"https:\/\/www.naraeon.net\/en\/pci-express-linkwidth-linkspeed\/","title":{"rendered":"Get PCI express link width \/ specification version Programmatically"},"content":{"rendered":"

Many people include me find how to get PCI express link width \/ specification version programmatically. But there’re too many useless articles. Like examples about NetworkAdapters(I applied “-NetworkAdapter” and 90% of search results are gone!). And some of the remaining results say it must be solved with drivers. Others say just give up windows and use linux(?).
\nUnfortunately now I don’t have any reference link, because of the catastrophic failure of my RAID1 storage<\/a>.<\/p>\n

1. WMI<\/h2>\n

Cannot do this. One of the answer from programdoc<\/a> says, even WMI specialist can’t do this.
\nI found a crude hack to do this. Please aware it’s a hack. I don’t guarantee anything about next queries.<\/p>\n

Firstly get DeviceID Property<\/span> of drive.
\nASSOCIATORS OF {Win32_DiskDrive.DeviceID=’\\\\.\\PhysicalDrive(Number)’} WHERE ResultClass=Win32_PnPEntity
\nThen get DeviceID\u00a0Property<\/span> of controller.
\nASSOCIATORS OF {Win32_PnPEntity.DeviceID='(DeviceID from above query result)’} WHERE AssocClass=Win32_SCSIControllerDevice
\nGet bus number(BusNum Property) of the controller.
\nASSOCIATORS OF {Win32_PnPEntity.DeviceID=‘(DeviceID from above query result)’} WHERE AssocClass=Win32_DeviceBus
\nLastly Find the bus number(BusNumber Property) in Win32_SystemSlot classes.
\nSELECT * FROM Win32_SystemSlot WHERE BusNumber='(BusNum from above query result)’
\n<\/span><\/span>
\nIn this way, you can find link width with MaxDataWidth property. Since it is gathered from SMBIOS, +3 from its value and you can read the value in SMBIOS way.
\nBut in this way you can’t get the specification version. Though SMBIOS specification has seperated value for 1.0, 2.0, 3.0 slot, mainboards like mine(B75M) only shows 1.0 value.
\nIn short, the problem is that, the relationship between bus and slot is hard to find.<\/p>\n

2. Driver<\/h2>\n

Read the PCI Express register. I didn’t tried this way. It needs too much efforts to do this small thing.<\/p>\n

3. WMI + SetupAPI<\/h2>\n

Here comes the ultimate solution.
\nFirstly execute to the second query at ‘1. WMI’ section. Then you’ll get DeviceID of the controller.
\nThen open the class with SetupDiGetClassDevs function. You can find class GUID at Device Manager \u2192 Select Device and Open Properties \u2192 Details \u2192 Class GUID.
\nTo find the device with the same DeviceID, iterate devices with SetupDiEnumDeviceInfo and get DeviceID with CM_Get_Device_IDW.
\nIf you find the device, use SetupDiGetDeviceProperty with next keys.<\/p>\n

DEVPKEY_PciDevice_CurrentLinkSpeed (pid: 9)
\nDEVPKEY_PciDevice_CurrentLinkWidth (pid: 10)
\nDEVPKEY_PciDevice_MaxLinkSpeed (pid: 11)
\nDEVPKEY_PciDevice_MaxLinkWidth (pid: 12)<\/p>\n

GUID for them is {3ab22e31-8264-4b4e-9af5-a8d2d8e33e62}.
\nMax- means maximum values that device supports, Current- means negotiated values.
\n-LinkSpeed represents specification version, -LinkWidth represents number of lanes. Be aware of LinkWidth value is the raw value so don’t try to read this in SMBIOS way.<\/p>\n","protected":false},"excerpt":{"rendered":"

Many people include me find how to get PCI express link width \/ specification version programmatically. But there’re too many useless articles. Like examples about NetworkAdapters(I applied “-NetworkAdapter” and 90% of search results are gone!). And some of the remaining results say it must be solved with drivers. Others say just give up windows and […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[57],"tags":[58,62,99,61,60,100],"class_list":["post-659","post","type-post","status-publish","format-standard","hentry","category-nvmetools","tag-nvme","tag-nvmexpress","tag-pciexpress","tag-samsung950","tag-samsung950pro","tag-wmi"],"translation":{"provider":"WPGlobus","version":"3.0.2","language":"en","enabled_languages":["kr","en"],"languages":{"kr":{"title":true,"content":true,"excerpt":false},"en":{"title":true,"content":true,"excerpt":false}}},"_links":{"self":[{"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/posts\/659","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/comments?post=659"}],"version-history":[{"count":12,"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/posts\/659\/revisions"}],"predecessor-version":[{"id":1862,"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/posts\/659\/revisions\/1862"}],"wp:attachment":[{"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/media?parent=659"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/categories?post=659"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.naraeon.net\/en\/wp-json\/wp\/v2\/tags?post=659"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}