Re: [PATCH] [media] solo6x10: avoid delayed register write

From: Andrey Utkin
Date: Mon Oct 17 2016 - 14:53:16 EST


On Thu, Sep 22, 2016 at 03:03:31AM +0300, Andrey Utkin wrote:
> 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.
>
> Signed-off-by: Andrey Utkin <andrey.utkin@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/media/pci/solo6x10/solo6x10.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/media/pci/solo6x10/solo6x10.h b/drivers/media/pci/solo6x10/solo6x10.h
> index 5bd4987..3f8da5e 100644
> --- a/drivers/media/pci/solo6x10/solo6x10.h
> +++ b/drivers/media/pci/solo6x10/solo6x10.h
> @@ -284,7 +284,10 @@ 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)
> --
> 2.9.2
>

Mauro, Hans,
Please pick this up. This has been around for a month, I expected it
would get to v4.9-rc1 easily.
Thanks.