{"id":1703,"date":"2016-04-21T02:45:38","date_gmt":"2016-04-21T01:45:38","guid":{"rendered":"http:\/\/rglinuxtech.com\/?p=1703"},"modified":"2016-05-23T09:45:54","modified_gmt":"2016-05-23T08:45:54","slug":"arm-rock2-kernel-4-6-rc4-mmc-swaparound-bug-or-feature","status":"publish","type":"post","link":"https:\/\/rglinuxtech.com\/?p=1703","title":{"rendered":"ARM – Rock2 – Kernel 4.6-rc4 – MMC Swaparound – Bug or Feature?"},"content":{"rendered":"

I had been running Kernel 4.6-rc2 on the Radxa Rock2 without any issues, and decided to update to recently-released Kernel 4.6-rc4<\/strong>..<\/p>\n

Brief details of changes from -rc3 are here:\u00a0 http:\/\/lkml.iu.edu\/hypermail\/linux\/kernel\/1604.2\/00610.html<\/a><\/p>\n

The boot failed, and I then compiled\/installed 4.6-rc3 to see if that<\/span> would have been OK, and it was..<\/p>\n

I then noticed something odd in the failed boot process… It appeared that the MMC device references had swapped around in -rc4:<\/p>\n

RC3 – and earlier (boot OK):<\/p>\n

...........<\/span><\/strong>\r\nmmc0: new high speed SDXC card at address e624<\/span><\/strong>\r\nmmcblk1: mmc0:e624 SL64G 59.5 GiB<\/span><\/strong>\r\n mmcblk1: p1<\/span><\/strong>\r\n...........<\/span><\/strong><\/pre>\n
RC4 (boot failed):<\/p>\n
...........<\/span><\/strong>\r\nmmc0: new high speed SDXC card at address e624<\/span><\/strong>\r\nmmcblk0: mmc0:e624 SL64G 59.5 GiB<\/span><\/strong>\r\n mmcblk0: p1<\/span><\/strong>\r\n...........<\/span><\/strong><\/pre>\n
So… a simple change to the u-boot kernel boot command – changing root=\/dev\/mmcblk1p1<\/span><\/strong> to root=\/dev\/mmcblk0p1<\/span><\/strong> – fixed the problem, and 4.6-rc4 booted OK..<\/p>\n
Fedora 23 (Twenty Three)\r\nKernel 4.6.0-rc4 on an armv7l (ttyS2)\r\n...............\r\n]# uname -a\r\nLinux rgrock2 4.6.0-rc4 #1 SMP Wed Apr 20 18:44:57 EDT 2016 armv7l armv7l armv7l GNU\/Linux<\/span><\/strong><\/pre>\n
All that was needed then, was to change \/etc\/fstab<\/span> accordingly.. (Yes – I still use the ‘traditional’ format!)<\/p>\n
Initial investigation suggested that this might be the kernel patch responsible:\u00a0 http:\/\/lkml.iu.edu\/hypermail\/linux\/kernel\/1604.0\/04340.html<\/a><\/p>\n
On the Rock2, this means that the on-board eMMC is now \/dev\/mmcblk1<\/span>, and the SDcard is \/dev\/mmcblk0<\/span>…\u00a0\u00a0 It will be interesting to see if this change affects any of my other ARM devices…..<\/p>\n
Robert Gadsdon. April 20, 2016.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"
I had been running Kernel 4.6-rc2 on the Radxa Rock2 without any issues, and decided to update to recently-released Kernel 4.6-rc4.. Brief details of changes from -rc3 are here:\u00a0 http:\/\/lkml.iu.edu\/hypermail\/linux\/kernel\/1604.2\/00610.html The boot failed, and I then compiled\/installed 4.6-rc3 to see if that would have been OK, and it was.. I then noticed something odd in the failed …<\/span> Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[1280,1238,11,14,16,1276,1274,350,937],"tags":[1174,1329,242,1330,296,1281,1282,1175,418],"class_list":["post-1703","post","type-post","status-publish","format-standard","hentry","category-boot","category-fix","category-hacks","category-kernel","category-linux-arm","category-radxa","category-rock2","category-success","category-u-boot-2","tag-arm","tag-kernel-4-6-rc4","tag-linux","tag-mmc-swapped","tag-patch","tag-radxa","tag-rock2","tag-success","tag-workaround"],"_links":{"self":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/1703","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1703"}],"version-history":[{"count":4,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/1703\/revisions"}],"predecessor-version":[{"id":1744,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/1703\/revisions\/1744"}],"wp:attachment":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1703"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1703"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1703"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}