Em Wed, 19 Dec 2018 11:07:01 -0600
Brad Love <brad@xxxxxxxxxxxxxxxx> escreveu:
> 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 <brad@xxxxxxxxxxxxxxxx>
Thanks!
Patch applied and sent upstream.
Regards,
Mauro
> ---
> Since v2:
> - Replaced sizeof with ARRAY_SIZE
> - Fixed column 80 checkpatch complaint
> 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 | 55 ++++++++++++++++++++++++++++++--
> drivers/media/pci/cx23885/cx23885.h | 2 ++
> 2 files changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/pci/cx23885/cx23885-core.c b/drivers/media/pci/cx23885/cx23885-core.c
> index 39804d8..e2e3649 100644
> --- a/drivers/media/pci/cx23885/cx23885-core.c
> +++ b/drivers/media/pci/cx23885/cx23885-core.c
> @@ -23,6 +23,7 @@
> #include <linux/moduleparam.h>
> #include <linux/kmod.h>
> #include <linux/kernel.h>
> +#include <linux/pci.h>
> #include <linux/slab.h>
> #include <linux/interrupt.h>
> #include <linux/delay.h>
> @@ -41,6 +42,18 @@ MODULE_AUTHOR("Steven Toth <stoth@xxxxxxxxxxx>");
> MODULE_LICENSE("GPL");
> MODULE_VERSION(CX23885_VERSION);
>
> +/*
> + * Some platforms have been found to require periodic resetting of the DMA
> + * engine. Ryzen and XEON platforms are known to be affected. The symptom
> + * encountered is "mpeg risc op code error". Only Ryzen platforms employ
> + * this workaround if the option equals 1. The workaround can be explicitly
> + * disabled for all platforms by setting to 0, the workaround can be forced
> + * on for any platform by setting to 2.
> + */
> +static unsigned int dma_reset_workaround = 1;
> +module_param(dma_reset_workaround, int, 0644);
> +MODULE_PARM_DESC(dma_reset_workaround, "periodic RiSC dma engine reset; 0-force disable, 1-driver detect (default), 2-force enable");
> +
> static unsigned int debug;
> module_param(debug, int, 0644);
> MODULE_PARM_DESC(debug, "enable debug messages");
> @@ -603,8 +616,13 @@ static void cx23885_risc_disasm(struct cx23885_tsport *port,
>
> static void cx23885_clear_bridge_error(struct cx23885_dev *dev)
> {
> - uint32_t reg1_val = cx_read(TC_REQ); /* read-only */
> - uint32_t reg2_val = cx_read(TC_REQ_SET);
> + uint32_t reg1_val, reg2_val;
> +
> + if (!dev->need_dma_reset)
> + return;
> +
> + reg1_val = cx_read(TC_REQ); /* read-only */
> + reg2_val = cx_read(TC_REQ_SET);
>
> if (reg1_val && reg2_val) {
> cx_write(TC_REQ, reg1_val);
> @@ -2058,6 +2076,37 @@ 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 < ARRAY_SIZE(broken_dev_id); i++) {
> + 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 +2118,8 @@ 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)
Thanks,
Mauro
