Hello, I've been writing some drivers for Linux-can in the past years and want to add support of MSI in one of them (see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/can/peak_canfd). This device driver works with legacy shared INTx over a CAN PCIe device. I'd like to switch to a full MSI usage of this device, which proposes up to 4 vectors (this device is proposed with 1, 2 or 4 CAN FD ports). I'm running x86_64 Kernel 4.13.0-32 from Ubuntu 17.10. Everything looks ok as I successfully get the 4 consecutive IRQ levels. My problem is this one: as soon as the driver free_irq() the FISRT IRQ level, then it does not receive any interrupt from the device anymore, for all other 3 IRQs... On the contrary, when the driver free_irq() one of the 3 other IRQ (instead of the 1st one), then there is no problem and all other interrupts (including the first IRQ vector) are working as they should. I contact you because this "issue" seems to be arch dependent: running the same driver and the same board on another arch (ARM), then everything works like a charm: the driver can free_irq() any IRQ in any order without disturbing the other ones. But running on x86, free_irq() on the FIRST MSI seems to (also) free all the other ones... Note that the driver set up MSI as described in the last version of Documentation/PCI/MSI-HOWTO.txt. Many thanks for your help in fixing this issue. --- Stéphane Grosjean PEAK-System France 132, rue André Bisiaux F54320 MAXEVILLE Tél : +(33) 9.72.54.51.97 -- PEAK-System Technik GmbH Sitz der Gesellschaft Darmstadt - HRB 9183 Geschaeftsfuehrung: Alexander Gach / Uwe Wilhelm --
