4.20-stable review patch. If anyone has any objections, please let me know.
------------------
From: Brad Love brad@nextdimension.cc
commit 4bd46aa0353e022c2401a258e93b107880a66533 upstream.
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@nextdimension.cc Signed-off-by: Mauro Carvalho Chehab mchehab+samsung@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/media/pci/cx23885/cx23885-core.c | 55 +++++++++++++++++++++++++++++-- drivers/media/pci/cx23885/cx23885.h | 2 + 2 files changed, 55 insertions(+), 2 deletions(-)
--- 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@linuxt 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 c
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_ /* TODO: 23-19 */ }
+static struct { + int vendor, dev; +} const broken_dev_id[] = { + /* According with + * https://openbenchmarking.org/system/1703021-RI-AMDZEN08075/Ryzen%207%201800X..., + * 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_de 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; --- 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)