| Message ID | 1545239221-9393-1-git-send-email-brad@nextdimension.cc (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] cx23885: only reset DMA on problematic CPUs | expand |
Em Wed, 19 Dec 2018 11:07:01 -0600 Brad Love <brad@nextdimension.cc> 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@nextdimension.cc> 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@linuxtv.org>"); > 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
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@linuxtv.org>"); 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)
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> --- 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(-)