---------- Forwarded message --------- From: Patrick Volkerding <volkerdi@xxxxxxxxx> Date: Tue, Jul 14, 2020 at 2:22 PM Subject: Hybrid graphics regression in 5.4.49+ [bisected] To: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>, Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Cc: Patrick Volkerding <volkerdi@xxxxxxxxx> Hello, I ran into a problem recently with a laptop with hybrid graphics. Here are the specs of the machine: OS: Slackware 14.2 x86_64 (post 14.2 -current) x86_64 Host: 20QV000GUS ThinkPad X1 Extreme 2nd CPU: Intel i7-9850H (12) @ 4.600GHz GPU: NVIDIA GeForce GTX 1650 Mobile / Max-Q GPU: Intel UHD Graphics 630 The graphics are set to hybrid in the BIOS, and no proprietary drivers are in use. With 5.4.48, starting X from a console works as expected and the Intel UHD Graphics 630 is used. Starting with 5.4.49, attempting to start X from a console causes the machine to become unresponsive, and thousands of these messages are found in the syslog: Jul 1 14:39:26 z-mp kernel: [ 1657.318941] nouveau 0000:01:00.0: fifo: PBDMA0: 01000000 [] ch 0 [00ff992000 DRM] subc 0 mthd 0008 data 00000000 A git bisect between 5.4.48 and 5.4.49 pointed to the commit [828b192c57e8f4fee77f7a34bd19c1b58b049dad] PCI/PM: Assume ports without DLL Link Active train links in 100 ms. The commit reverts cleanly from 5.4.51, and then that kernel works as expected. Additionally I should note that an unmodified kernel 5.7.7 also works as expected. Happy to help test any proposed fix. Here's the git bisect log: git bisect start # good: [67cb016870e2fa9ffc8d34cf20db5331e6f2cf4d] Linux 5.4.48 git bisect good 67cb016870e2fa9ffc8d34cf20db5331e6f2cf4d # good: [67cb016870e2fa9ffc8d34cf20db5331e6f2cf4d] Linux 5.4.48 git bisect good 67cb016870e2fa9ffc8d34cf20db5331e6f2cf4d # bad: [99705220b22ca116457edeae51ae817d056a6622] net: core: device_rename: Use rwsem instead of a seqcount git bisect bad 99705220b22ca116457edeae51ae817d056a6622 # bad: [7454c171a88c188583bbfe17db1f9e6e75723b5f] tty: n_gsm: Fix bogus i++ in gsm_data_kick git bisect bad 7454c171a88c188583bbfe17db1f9e6e75723b5f # good: [390f1688fb4648474b29c8ea6c2c710b689cd669] f2fs: handle readonly filesystem in f2fs_ioc_shutdown() git bisect good 390f1688fb4648474b29c8ea6c2c710b689cd669 # good: [9eb54d0e8962d2f5d7a430f3a245037c990e3b42] PCI: v3-semi: Fix a memory leak in v3_pci_probe() error handling paths git bisect good 9eb54d0e8962d2f5d7a430f3a245037c990e3b42 # good: [4536dbe64bd17b7d16cb0da56a15616dda247940] USB: ohci-sm501: fix error return code in ohci_hcd_sm501_drv_probe() git bisect good 4536dbe64bd17b7d16cb0da56a15616dda247940 # bad: [b1bc8753eefc82b79e285977c6177c67bc17344e] ipmi: use vzalloc instead of kmalloc for user creation git bisect bad b1bc8753eefc82b79e285977c6177c67bc17344e # good: [860b8717f7247384e500ba15c89e9b5327d00423] tty: n_gsm: Fix waking up upper tty layer when room available git bisect good 860b8717f7247384e500ba15c89e9b5327d00423 # good: [c6737f3a1b01120ce0991bb0b6b4c8da2b086f1e] HID: Add quirks for Trust Panora Graphic Tablet git bisect good c6737f3a1b01120ce0991bb0b6b4c8da2b086f1e # bad: [5c2207ba2394ee6c2dd7383890818aca89ff4b9b] habanalabs: increase timeout during reset git bisect bad 5c2207ba2394ee6c2dd7383890818aca89ff4b9b # bad: [828b192c57e8f4fee77f7a34bd19c1b58b049dad] PCI/PM: Assume ports without DLL Link Active train links in 100 ms git bisect bad 828b192c57e8f4fee77f7a34bd19c1b58b049dad # first bad commit: [828b192c57e8f4fee77f7a34bd19c1b58b049dad] PCI/PM: Assume ports without DLL Link Active train links in 100 ms Best regards, Pat
