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 <stoth@xxxxxxxxxxxxxx> Signed-off-by: Brendan McGrath <redmcg@xxxxxxxxxxxxxxxxxxx> --- Changes since v3: - fixes a conflict with a commit (3f845f3c4cf4) made to the media_tree after v3 was created (only the unified context has been changed) - corrected comments to reflect that the reported incident occured more commonly when multiple tuners were in use (not multiple saa7164 chips as previously stated) drivers/media/pci/saa7164/saa7164-core.c | 40 ++++++++++++++++++++++++++++++-- drivers/media/pci/saa7164/saa7164.h | 1 + 2 files changed, 39 insertions(+), 2 deletions(-) diff --git a/drivers/media/pci/saa7164/saa7164-core.c b/drivers/media/pci/saa7164/saa7164-core.c index 9cf3c6c..7635598 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); @@ -1230,8 +1235,34 @@ 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); + /* irq bit */ + if (enable_msi) + err = pci_enable_msi(pci_dev); + + if (!err && enable_msi) { + /* 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); + } else { + dev->msi = true; + } + } + + if ((!enable_msi) || err) { + dev->msi = false; + /* 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); @@ -1439,6 +1470,11 @@ 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 cd1a07c..6df4b252 100644 --- a/drivers/media/pci/saa7164/saa7164.h +++ b/drivers/media/pci/saa7164/saa7164.h @@ -459,6 +459,7 @@ struct saa7164_dev { /* Interrupt status and ack registers */ u32 int_status; u32 int_ack; + u32 msi; struct cmd cmds[SAA_CMD_MAX_MSG_UNITS]; struct mutex lock; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
