Currently in ath11k we keep the firmware running on the WLAN device when the network interface (wlan0) is down. The problem is that this will break hibernation, obviously the firmware can't be running after the whole system is powered off. To power down the ath11k firmware for suspend/hibernation some changes both in MHI subsystem and ath11k are needed. This patchset fixes a longstanding bug report about broken hibernation support: https://bugzilla.kernel.org/show_bug.cgi?id=214649 There already is an RFC version which has been tested by multiple users with positive results: https://patchwork.kernel.org/project/linux-wireless/cover/20231127162022.518834-1-kvalo@xxxxxxxxxx/ Basically the RFC version adds two APIs to MHI stack: with the first one ath11k is able to keep MHI devices when going to suspend/hibernation, getting us rid of the probe deferral issue when resume back. while with the second one ath11k could manually prepare/unprepare MHI channels by itself, which is needed because QRTR doesn't probe those channels automatically in this case. Mani, the MHI maintainer, firstly doesn't like that version and insists that an MHI device should be destroyed when suspend/hibernation, according to his understanding on device driver model. See https://lore.kernel.org/mhi/20231127162022.518834-1-kvalo@xxxxxxxxxx/ After a long discussion Mani thought we might need a new PM callback with which ath11k is able to wait until kernel unblocks device probe and thus MHI channels get probed. So we came to the kernel PM list and there Mani realized that his understanding is not correct so he finally agrees to keep MHI device during suspend/hibernation. See https://lore.kernel.org/all/21cd2098-97e1-4947-a5bb-a97582902ead@xxxxxxxxxxx/ Mani also pointed out that an MHI controller driver (ath11k here) should not touch MHI channels directly because those channels are managed by the corresponding MHI client driver (QRTR here). To address this, we come up with this version. Compared with that RFC version, this version adds PM callbacks in QRTR module: suspend callback unprepares MHI channels during suspend and resume callback prepares those channels during resume. In this way ath11k doesn't need to do unprepare/prepare work by itself so those two APIs added in RFC version are removed now. The power down/up procedure requires a specific sequence in which PM callbacks of wiphy, ath11k and QRTR are called, this is achieved by exploiting the child-father relationship between their device struct, and also the PM framework which separates whole suspend/resume process into several stages. Details in patch [3/3]. Depends on: wifi: ath11k: rearrange IRQ enable/disable in reset path wifi: ath11k: remove MHI LOOPBACK channels wifi: ath11k: do not dump SRNG statistics during resume wifi: ath11k: fix warning on DMA ring capabilities event wifi: ath11k: thermal: don't try to register multiple times Baochen Qiang (3): bus: mhi: host: add mhi_power_down_no_destroy() net: qrtr: support suspend/hibernation wifi: ath11k: support hibernation drivers/bus/mhi/host/internal.h | 4 +- drivers/bus/mhi/host/pm.c | 36 +++++++-- drivers/net/wireless/ath/ath11k/ahb.c | 6 +- drivers/net/wireless/ath/ath11k/core.c | 105 +++++++++++++++++-------- drivers/net/wireless/ath/ath11k/core.h | 6 +- drivers/net/wireless/ath/ath11k/hif.h | 14 +++- drivers/net/wireless/ath/ath11k/mhi.c | 12 ++- drivers/net/wireless/ath/ath11k/mhi.h | 5 +- drivers/net/wireless/ath/ath11k/pci.c | 44 +++++++++-- drivers/net/wireless/ath/ath11k/qmi.c | 2 +- include/linux/mhi.h | 15 +++- net/qrtr/mhi.c | 29 +++++++ 12 files changed, 218 insertions(+), 60 deletions(-) base-commit: 707e306f3573fa321ae197d77366578e4566cff5 prerequisite-patch-id: d3f76112f9a55195c71459e0edf3a4ecf8af9181 prerequisite-patch-id: 340d15aad1d3c1c3c93d9d996e1c96226c8bad8f prerequisite-patch-id: 98cdd37a68df4f651a065145e946d92c43be799e prerequisite-patch-id: a19ed13af0c894b7f9b22cedc99029991f48e47c prerequisite-patch-id: b5ad50fae6167c7c2b60cc063a8d460f7ddd4997 -- 2.25.1
