It could be related to the fact that a PCI write may be delayed unless it is followed by a read (see also the comments in drivers/media/pci/ivtv/ivtv-driver.h). That was probably the reason for the pci_read_config_word in the reg_write code. Try putting that back (and just that). Regards, Hans On 09/15/2016 03:04 PM, Andrey Utkin wrote: > Hi Krzysztof, > > Me and one more solo6010 board user experience machine lockup when > solo6x10 module is loaded on kernel series starting with 4.3 (despite > solo6110 board probes just fine on all kernels). That is, 3.16, 3.18, > 4.1 and 4.2 are tested and fine, and 4.3, 4.4, and others up to current > linux-next are bad. > So regression slipped in between 4.2 and 4.3. The diff between > stable/linux-4.2.y and ...-4.3.y (which were tested) is not large, and > my suspect fell on ripoff of register writing procedures complexity, > which was introduced in e1ceb25a (see below). Reversion of that fixes > lockup. However, if, on top of reversion of e1ceb25a, i drop barrier > stuff and pci_read_config... (see > https://github.com/bluecherrydvr/linux/commit/d59aaf3), leaving the > spinlock stuff, it locks up again. This is a matter in which I'm not > quite qualified, so I have no idea what that code copes with and why > this workaround works for solo6010. For now I think I'll tell the > customer to use kernel with e1ceb25a reverted, but for upstream fix, I'm > interested in more in-depth investigation. I'll be able to provide dmesg > logs a bit later. > > The breaking commit is quoted below. > > commit e1ceb25a1569ce5b61b9c496dd32d038ba8cb936 > Author: Krzysztof Hałasa <khalasa@xxxxxxx> > Date: Mon Jun 8 10:42:24 2015 -0300 > > [media] SOLO6x10: remove unneeded register locking and barriers > > readl() and writel() are atomic, we don't need the spin lock. > Also, flushing posted write buffer isn't required. Especially on read :-) > > Signed-off-by: Krzysztof Ha?asa <khalasa@xxxxxxx> > Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> > Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx> > > diff --git a/drivers/media/pci/solo6x10/solo6x10-core.c b/drivers/media/pci/solo6x10/solo6x10-core.c > index 84627e6..9c948b1 100644 > --- a/drivers/media/pci/solo6x10/solo6x10-core.c > +++ b/drivers/media/pci/solo6x10/solo6x10-core.c > @@ -483,7 +483,6 @@ static int solo_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > solo_dev->type = id->driver_data; > solo_dev->pdev = pdev; > - spin_lock_init(&solo_dev->reg_io_lock); > ret = v4l2_device_register(&pdev->dev, &solo_dev->v4l2_dev); > if (ret) > goto fail_probe; > diff --git a/drivers/media/pci/solo6x10/solo6x10.h b/drivers/media/pci/solo6x10/solo6x10.h > index 1ca54b0..27423d7 100644 > --- a/drivers/media/pci/solo6x10/solo6x10.h > +++ b/drivers/media/pci/solo6x10/solo6x10.h > @@ -199,7 +199,6 @@ struct solo_dev { > int nr_ext; > u32 irq_mask; > u32 motion_mask; > - spinlock_t reg_io_lock; > struct v4l2_device v4l2_dev; > > /* tw28xx accounting */ > @@ -281,36 +280,13 @@ struct solo_dev { > > static inline u32 solo_reg_read(struct solo_dev *solo_dev, int reg) > { > - unsigned long flags; > - u32 ret; > - u16 val; > - > - spin_lock_irqsave(&solo_dev->reg_io_lock, flags); > - > - ret = readl(solo_dev->reg_base + reg); > - rmb(); > - pci_read_config_word(solo_dev->pdev, PCI_STATUS, &val); > - rmb(); > - > - spin_unlock_irqrestore(&solo_dev->reg_io_lock, flags); > - > - return ret; > + return readl(solo_dev->reg_base + reg); > } > > static inline void solo_reg_write(struct solo_dev *solo_dev, int reg, > u32 data) > { > - unsigned long flags; > - u16 val; > - > - spin_lock_irqsave(&solo_dev->reg_io_lock, flags); > - > writel(data, solo_dev->reg_base + reg); > - wmb(); > - pci_read_config_word(solo_dev->pdev, PCI_STATUS, &val); > - rmb(); > - > - spin_unlock_irqrestore(&solo_dev->reg_io_lock, flags); > } > > static inline void solo_irq_on(struct solo_dev *dev, u32 mask) > -- > 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 > -- 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
