Am 18.12.18 um 23:59 schrieb Brad Love:
> It is reported that commit 95f408bbc4e4 ("media: cx23885: Ryzen DMA
> related RiSC engine stall fixes") caused regresssions with other CPUs.
>
> Ensure that the quirk will be applied only for the CPUs that
> are known to cause problems.
>
> A module option is added for explicit control of the behaviour.
>
> Fixes: 95f408bbc4e4 ("media: cx23885: Ryzen DMA related RiSC engine stall
> fixes")
>
> Signed-off-by: Brad Love <[email protected]>
Hi Brad,
I found one issue. See below.
Regards
Matthias
> ---
> Changes since v1:
> - Added module option for three way control
> - Removed '7' from pci id description, Ryzen 3 is the same id
>
> drivers/media/pci/cx23885/cx23885-core.c | 54
> ++++++++++++++++++++++++++++++--
> drivers/media/pci/cx23885/cx23885.h | 2 ++
> 2 files changed, 54 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/pci/cx23885/cx23885-core.c
> b/drivers/media/pci/cx23885/cx23885-core.c
> index 39804d8..fb721c7 100644
> --- a/drivers/media/pci/cx23885/cx23885-core.c
> +++ b/drivers/media/pci/cx23885/cx23885-core.c
...
> @@ -2058,6 +2076,36 @@ void cx23885_gpio_enable(struct cx23885_dev *dev, u32
> mask, int asoutput)
> /* TODO: 23-19 */
> }
>
> +static struct {
> + int vendor, dev;
> +} const broken_dev_id[] = {
> + /* According with
> + *
> https://openbenchmarking.org/system/1703021-RI-AMDZEN08075/Ryzen%207%201800X/lspci,
> + * 0x1451 is PCI ID for the IOMMU found on Ryzen
> + */
> + { PCI_VENDOR_ID_AMD, 0x1451 },
> +};
> +
> +static bool cx23885_does_need_dma_reset(void)
> +{
> + int i;
> + struct pci_dev *pdev = NULL;
> +
> + if (dma_reset_workaround == 0)
> + return false;
> + else if (dma_reset_workaround == 2)
> + return true;
> +
> + for (i = 0; i < sizeof(broken_dev_id); i++) {
This is broken. sizeof delivers the size in bytes, not in number of
array elements. ARRAY_SIZE is what you want.
> + pdev = pci_get_device(broken_dev_id[i].vendor,
> broken_dev_id[i].dev, NULL);
> + if (pdev) {
> + pci_dev_put(pdev);
> + return true;
> + }
> + }
> + return false;
> +}
> +
> static int cx23885_initdev(struct pci_dev *pci_dev,
> const struct pci_device_id *pci_id)
> {
> @@ -2069,6 +2117,8 @@ static int cx23885_initdev(struct pci_dev *pci_dev,
> if (NULL == dev)
> return -ENOMEM;
>
> + dev->need_dma_reset = cx23885_does_need_dma_reset();
> +
> err = v4l2_device_register(&pci_dev->dev, &dev->v4l2_dev);
> if (err < 0)
> goto fail_free;
> diff --git a/drivers/media/pci/cx23885/cx23885.h
> b/drivers/media/pci/cx23885/cx23885.h
> index d54c7ee..cf965ef 100644
> --- a/drivers/media/pci/cx23885/cx23885.h
> +++ b/drivers/media/pci/cx23885/cx23885.h
> @@ -451,6 +451,8 @@ struct cx23885_dev {
> /* Analog raw audio */
> struct cx23885_audio_dev *audio_dev;
>
> + /* Does the system require periodic DMA resets? */
> + unsigned int need_dma_reset:1;
> };
>
> static inline struct cx23885_dev *to_cx23885(struct v4l2_device *v4l2_dev)
>
