Re: linux 4.2-rc1 broken Nokia N900

[Michael Welling <mwelling@ieee.org>]

On Tue, Jul 21, 2015 at 11:34:41AM +0200, Pavel Machek wrote:

This code has my head spinning.

I found that the errors do not occur when the driver is built into the kernel.

I also found that with the patch below the errors go away.

Not sure if it is acceptible but see if it fixes things on your side.


diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index cf8b91b..3164d13 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1801,11 +1801,11 @@ int spi_setup(struct spi_device *spi)
 	if (!spi->max_speed_hz)
 		spi->max_speed_hz = spi->master->max_speed_hz;
 
-	spi_set_cs(spi, false);
-
 	if (spi->master->setup)
 		status = spi->master->setup(spi);
 
+	spi_set_cs(spi, false);
+
 	dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
 			(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
 			(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",