From 77978089ddc90347644cc057e6b6cd169ac9abd4 Mon Sep 17 00:00:00 2001 From: Brendan McGrath Date: Fri, 10 Apr 2015 03:39:22 -0300 Subject: [PATCH] [media] saa7164: use an MSI interrupt when available Enhances driver to use an MSI interrupt when available. Adds the module option 'enable_msi' (type bool) which by default is enabled. Can be set to 'N' to disable. Fixes (or can reduce the occurrence of) a crash which is most commonly reported when both digital tuners of the saa7164 chip is in use. A reported example can be found here: http://permalink.gmane.org/gmane.linux.drivers.video-input-infrastructure/83948 Reviewed-by: Steven Toth Signed-off-by: Brendan McGrath Signed-off-by: Mauro Carvalho Chehab --- drivers/media/pci/saa7164/saa7164-core.c | 66 +++++++++++++++++++++--- drivers/media/pci/saa7164/saa7164.h | 1 + 2 files changed, 60 insertions(+), 7 deletions(-) diff --git a/drivers/media/pci/saa7164/saa7164-core.c b/drivers/media/pci/saa7164/saa7164-core.c index 90de80726f0a..3206a826b80d 100644 --- a/drivers/media/pci/saa7164/saa7164-core.c +++ b/drivers/media/pci/saa7164/saa7164-core.c @@ -85,6 +85,11 @@ module_param(guard_checking, int, 0644); MODULE_PARM_DESC(guard_checking, "enable dma sanity checking for buffer overruns"); +static bool enable_msi = true; +module_param(enable_msi, bool, 0444); +MODULE_PARM_DESC(enable_msi, + "enable the use of an msi interrupt if available"); + static unsigned int saa7164_devcount; static DEFINE_MUTEX(devlist); @@ -1186,6 +1191,39 @@ static int saa7164_thread_function(void *data) return 0; } +static bool saa7164_enable_msi(struct pci_dev *pci_dev, struct saa7164_dev *dev) +{ + int err; + + if (!enable_msi) { + printk(KERN_WARNING "%s() MSI disabled by module parameter 'enable_msi'" + , __func__); + return false; + } + + err = pci_enable_msi(pci_dev); + + if (err) { + printk(KERN_ERR "%s() Failed to enable MSI interrupt." + " Falling back to a shared IRQ\n", __func__); + return false; + } + + /* no error - so request an msi interrupt */ + err = request_irq(pci_dev->irq, saa7164_irq, 0, + dev->name, dev); + + if (err) { + /* fall back to legacy interrupt */ + printk(KERN_ERR "%s() Failed to get an MSI interrupt." + " Falling back to a shared IRQ\n", __func__); + pci_disable_msi(pci_dev); + return false; + } + + return true; +} + static int saa7164_initdev(struct pci_dev *pci_dev, const struct pci_device_id *pci_id) { @@ -1232,13 +1270,22 @@ static int saa7164_initdev(struct pci_dev *pci_dev, goto fail_irq; } - err = request_irq(pci_dev->irq, saa7164_irq, - IRQF_SHARED, dev->name, dev); - if (err < 0) { - printk(KERN_ERR "%s: can't get IRQ %d\n", dev->name, - pci_dev->irq); - err = -EIO; - goto fail_irq; + /* irq bit */ + if (saa7164_enable_msi(pci_dev, dev)) { + dev->msi = true; + } else { + /* if we have an error (i.e. we don't have an interrupt) + or msi is not enabled - fallback to shared interrupt */ + + err = request_irq(pci_dev->irq, saa7164_irq, + IRQF_SHARED, dev->name, dev); + + if (err < 0) { + printk(KERN_ERR "%s: can't get IRQ %d\n", dev->name, + pci_dev->irq); + err = -EIO; + goto fail_irq; + } } pci_set_drvdata(pci_dev, dev); @@ -1441,6 +1488,11 @@ static void saa7164_finidev(struct pci_dev *pci_dev) /* unregister stuff */ free_irq(pci_dev->irq, dev); + if (dev->msi) { + pci_disable_msi(pci_dev); + dev->msi = false; + } + pci_disable_device(pci_dev); mutex_lock(&devlist); diff --git a/drivers/media/pci/saa7164/saa7164.h b/drivers/media/pci/saa7164/saa7164.h index 138f7f93ee7d..18906e0c80e1 100644 --- a/drivers/media/pci/saa7164/saa7164.h +++ b/drivers/media/pci/saa7164/saa7164.h @@ -464,6 +464,7 @@ struct saa7164_dev { /* Interrupt status and ack registers */ u32 int_status; u32 int_ack; + bool msi; struct cmd cmds[SAA_CMD_MAX_MSG_UNITS]; struct mutex lock; -- 2.20.1