media: solo6x10: fix lockup by avoiding delayed register write

commit 5fc4b067ec082c3127e0156f800769b7e0dce078 upstream.

This fixes a lockup at device probing which happens on some solo6010
hardware samples. This is a regression introduced by commit e1ceb25a1569
("[media] SOLO6x10: remove unneeded register locking and barriers")

The observed lockup happens in solo_set_motion_threshold() called from
solo_motion_config().

This extra "flushing" is not fundamentally needed for every write, but
apparently the code in driver assumes such behaviour at last in some
places.

Actual fix was proposed by Hans Verkuil.

Fixes: e1ceb25a1569 ("[media] SOLO6x10: remove unneeded register locking and barriers")
Signed-off-by: Andrey Utkin <andrey.utkin@corp.bluecherry.net>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/pci/solo6x10/solo6x10.h b/drivers/media/pci/solo6x10/solo6x10.h
index 4ab6586c0467529ea145452f2e534f30edeb2a73..f53e59e9c0eab2d27c169f5fb4dec0e7d8ea33b2 100644 (file)
--- a/drivers/media/pci/solo6x10/solo6x10.h
+++ b/drivers/media/pci/solo6x10/solo6x10.h
@@ -286,7 +286,10 @@ static inline u32 solo_reg_read(struct solo_dev *solo_dev, int reg)
 static inline void solo_reg_write(struct solo_dev *solo_dev, int reg,
                                  u32 data)
 {
+       u16 val;
+
        writel(data, solo_dev->reg_base + reg);
+       pci_read_config_word(solo_dev->pdev, PCI_STATUS, &val);
 }
 
 static inline void solo_irq_on(struct solo_dev *dev, u32 mask)