On 13 December 2016 at 19:37, Erik Stromdahl <erik.stromdahl@xxxxxxxxx> wrote: > > > On 12/13/2016 06:26 PM, Valo, Kalle wrote: >> Michal Kazior <michal.kazior@xxxxxxxxx> writes: >> >>> On 13 December 2016 at 14:44, Valo, Kalle <kvalo@xxxxxxxxxxxxxxxx> wrote: >>>> Erik Stromdahl <erik.stromdahl@xxxxxxxxx> writes: >>>> >>>>> Code refactorization: >>>>> >>>>> Moved the code for ep 0 in ath10k_htc_rx_completion_handler >>>>> to ath10k_htc_control_rx_complete. >>>>> >>>>> This eases the implementation of SDIO/mbox significantly since >>>>> the ep_rx_complete cb is invoked directly from the SDIO/mbox >>>>> hif layer. >>>>> >>>>> Since the ath10k_htc_control_rx_complete already is present >>>>> (only containing a warning message) there is no reason for not >>>>> using it (instead of having a special case for ep 0 in >>>>> ath10k_htc_rx_completion_handler). >>>>> >>>>> Signed-off-by: Erik Stromdahl <erik.stromdahl@xxxxxxxxx> >>>> >>>> I tested this on QCA988X PCI board just to see if there are any >>>> regressions. It crashes immediately during module load, every time, and >>>> bisected that the crashing starts on this patch: >>>> >>>> [ 1239.715325] ath10k_pci 0000:02:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 reset_mode 0 >>>> [ 1239.885125] ath10k_pci 0000:02:00.0: Direct firmware load for ath10k/pre-cal-pci-0000:02:00.0.bin failed with error -2 >>>> [ 1239.885260] ath10k_pci 0000:02:00.0: Direct firmware load for ath10k/cal-pci-0000:02:00.0.bin failed with error -2 >>>> [ 1239.885687] ath10k_pci 0000:02:00.0: qca988x hw2.0 target 0x4100016c chip_id 0x043202ff sub 0000:0000 >>>> [ 1239.885699] ath10k_pci 0000:02:00.0: kconfig debug 1 debugfs 1 tracing 1 dfs 1 testmode 1 >>>> [ 1239.885899] ath10k_pci 0000:02:00.0: firmware ver 10.2.4.70.59-2 api 5 features no-p2p,raw-mode,mfp,allows-mesh-bcast crc32 4159f498 >>>> [ 1239.941836] ath10k_pci 0000:02:00.0: Direct firmware load for ath10k/QCA988X/hw2.0/board-2.bin failed with error -2 >>>> [ 1239.941993] ath10k_pci 0000:02:00.0: board_file api 1 bmi_id N/A crc32 bebc7c08 >>>> [ 1241.136693] BUG: unable to handle kernel NULL pointer dereference at (null) >>>> [ 1241.136738] IP: [< (null)>] (null) >>>> [ 1241.136759] *pdpt = 0000000000000000 *pde = f0002a55f0002a55 [ 1241.136781] >>>> [ 1241.136793] Oops: 0010 [#1] SMP >>>> >>>> What's odd is that when I added some printks on my own and enabled both >>>> boot and htc debug levels it doesn't crash anymore. After everything >>>> works normally after that, I can start AP mode and connect to it. Is it >>>> a race somewhere? >>> >>> Yes. htc_wait_target() is called after hif_start(). The ep_rx_complete >>> is set in htc_wait_target() [changed patch 4, but still too late]. >>> >>> ep_rx_complete must be set prior to calling hif_start(). You probably >>> crash on end of ath10k_htc_rx_completion_handler() when trying to call >>> ep->ep_ops.ep_rx_complete(ar, skb). >> >> Yeah, just checked and ep->ep_ops.ep_rx_complete is NULL at the end of >> ath10k_htc_rx_completion_handler(). >> > It is indeed correct as Michal points out, there is a risk that the > first HTC control message (typically an HTC ready message) is received > before the HTC control endpoint is connected. > > I have experienced a similar race with my SDIO implementation as well. > In this case I did solve the issue by enabling HIF target interrupts > after the HTC control endpoint was connected. I am not sure however if > this is the most elegant way to solve this problem. > > My SDIO target won't send the HTC ready message before this is done. > The fix essentially consists of moving the ..._irg_enable call from > hif_start into another hif op. It makes more sense to move ep_rx_complete setup/assignment before hif_start(). This assignment should be done very early as there is nothing to change/override for this endpoint during operation, is there? It's known what it needs to store very early on. > I have made a few updates since I submitted the original RFC and created > a repo on github: > > https://github.com/erstrom/linux-ath > > I have a bunch of branches that are all based on the tags on the ath master. > > As of this moment the latest version is: > > ath-201612131156-ath10k-sdio > > This branch contains the original RFC patches plus some addons/fixes. > > In the above mentioned branch there are a few commits related to this > race condition. Perhaps you can have a look at them? > > The commits are: > 821672913328cf737c9616786dc28d2e4e8a4a90 I would avoid if(bus==xx) checks. > dd7fcf0a1f78e68876d14f90c12bd37f3a700ad7 > 7434b7b40875bd08a3a48a437ba50afed7754931 > > Perhaps this approach can work with PCIe as well? I think I did contemplate the unmask/start distinction at some point but I didn't go with it for some reason I can't recall now. Michał
