From 11058bd3d47d57eb3473935feae53868d6d168b7 Mon Sep 17 00:00:00 2001 From: Jasper Wise Date: Thu, 13 Aug 2026 08:46:18 +0000 Subject: [PATCH] spi: virtio: mark device ready before registering the controller virtio_spi_probe() registers the SPI controller with devm_spi_register_controller(). spi_register_controller() binds a child inline unless its driver has asked for asynchronous probing, so a peripheral that performs a transfer during its own probe reaches virtio_spi_transfer_one(), which kicks the virtqueue before probe has returned. The driver never calls virtio_device_ready(), so DRIVER_OK is set on its behalf by virtio_dev_probe(), only once probe has returned. The virtio spec is explicit about that ordering in 3.1 Device Initialization: | The driver MUST NOT send any buffer available notifications to the | device before setting DRIVER_OK. A device that waits for DRIVER_OK before servicing the queue therefore leaves the transfer unanswered, and virtio_spi_transfer_one() waits for its completion with no timeout, so probe never returns. Mark the device ready before registering the controller, as done for the same reason in commit f5866db64f34 ("virtio_console: enable VQs early") and commit 1d774589f924 ("i2c: virtio: mark device ready before registering the adapter"). Fixes: f98cabe3f6cf ("SPI: Add virtio SPI driver") Signed-off-by: Jasper Wise Link: https://patch.msgid.link/20260813084618.613172-1-jaspwise@amazon.co.uk Signed-off-by: Mark Brown --- drivers/spi/spi-virtio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/spi/spi-virtio.c b/drivers/spi/spi-virtio.c index fa4c68049eca..2256dfec5407 100644 --- a/drivers/spi/spi-virtio.c +++ b/drivers/spi/spi-virtio.c @@ -358,6 +358,8 @@ static int virtio_spi_probe(struct virtio_device *vdev) if (ret) return dev_err_probe(&vdev->dev, ret, "Cannot register virtqueue cleanup\n"); + virtio_device_ready(vdev); + /* Use devm version to register controller */ ret = devm_spi_register_controller(&vdev->dev, ctrl); if (ret) -- 2.47.3