Hi all, There is a known problem on some MacBooks: internal card reader disappears after the first suspend/resume and all subsequent attempts to suspend laptop are failing. This was reported[1][2] and even discussed in the mailing lists[3], without any real solution. After trying various things[4], including some existing quirks, I discovered that switching link state to DISABLED before suspend both fixes the card reader device and allows any subsequent suspend to succeed. First patch adds code for this new quirk, and second patch enables this quirk for card reader device which is used in my macbook. I'm not really familiar with either USB standards or kernel code to support them, so this patch series is RFC. I'm especially unsure with the "resume" part, because I implemented it by trial and error mostly. However, I'm using kernel with these patches and it works for me. Also, feel free to suggest other kernel patches or existing quirks or quirk combinations to fix the same problem. Oh, and by the way: I've checked schematics of various macbooks available on the internet. It seems that the actual chip is Genesys Logic GL3219, probably just with the custom ID. What I found curious, is that USB 2.0 pins of this chip (D+ and D-) are not really connected anywhere, but instead shorted through the resistor. Could it be possible that this somehow messes up some logic inside the device, host controller or linux kernel? [1] https://bugzilla.kernel.org/show_bug.cgi?id=111201 [2] https://bugzilla.kernel.org/show_bug.cgi?id=202509 [3] https://www.spinics.net/lists/linux-usb/msg164261.html [4] https://github.com/im-0/investigate-card-reader-suspend-problem-on-mbp11.4 Ivan Mironov (2): usb: core: Add support of disabling SS link before system suspend usb: quirks: Add quirk to fix card reader and suspend on MacBooks drivers/usb/core/driver.c | 6 +++ drivers/usb/core/hub.c | 84 ++++++++++++++++++++++++++++++++++++-- drivers/usb/core/quirks.c | 7 ++++ include/linux/usb.h | 3 ++ include/linux/usb/quirks.h | 9 ++++ 5 files changed, 105 insertions(+), 4 deletions(-) -- 2.20.1
