On Friday 26 February 2010 21:07:43 Linus Torvalds wrote:
>
> On Fri, 26 Feb 2010, Michael Buesch wrote:
> >
> > Where is that patch? I can't find it in any list archives.
>
> Here is the patch. I originally sent it to Larry directly (with John and
> David cc'd).
>
> Linus
>
> ---
> drivers/net/wireless/b43/Kconfig | 6 +++---
> drivers/net/wireless/b43/b43.h | 5 +++--
> drivers/net/wireless/b43/main.c | 10 +++++++++-
> 3 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/wireless/b43/Kconfig b/drivers/net/wireless/b43/Kconfig
> index 64c12e1..e6a7d8e 100644
> --- a/drivers/net/wireless/b43/Kconfig
> +++ b/drivers/net/wireless/b43/Kconfig
> @@ -78,11 +78,11 @@ config B43_SDIO
>
> If unsure, say N.
>
> -# Data transfers to the device via PIO
> -# This is only needed on PCMCIA and SDIO devices. All others can do DMA properly.
> +# Data transfers to the device via PIO. We want it as a fallback even
> +# if we can do DMA.
> config B43_PIO
> bool
> - depends on B43 && (B43_SDIO || B43_PCMCIA || B43_FORCE_PIO)
> + depends on B43
> select SSB_BLOCKIO
> default y
>
> diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h
> index c484cc2..f2cfbc4 100644
> --- a/drivers/net/wireless/b43/b43.h
> +++ b/drivers/net/wireless/b43/b43.h
> @@ -694,6 +694,7 @@ struct b43_wldev {
> bool radio_hw_enable; /* saved state of radio hardware enabled state */
> bool qos_enabled; /* TRUE, if QoS is used. */
> bool hwcrypto_enabled; /* TRUE, if HW crypto acceleration is enabled. */
> + bool use_pio; /* TRUE if next init should use PIO */
>
> /* PHY/Radio device. */
> struct b43_phy phy;
> @@ -885,9 +886,9 @@ static inline bool b43_using_pio_transfers(struct b43_wldev *dev)
> }
>
> #ifdef CONFIG_B43_FORCE_PIO
> -# define B43_FORCE_PIO 1
> +# define B43_PIO_DEFAULT 1
> #else
> -# define B43_FORCE_PIO 0
> +# define B43_PIO_DEFAULT 0
> #endif
>
>
> diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
> index 490fb45..d310ce7 100644
> --- a/drivers/net/wireless/b43/main.c
> +++ b/drivers/net/wireless/b43/main.c
> @@ -98,6 +98,10 @@ static int modparam_btcoex = 1;
> module_param_named(btcoex, modparam_btcoex, int, 0444);
> MODULE_PARM_DESC(btcoex, "Enable Bluetooth coexistence (default on)");
>
> +int b43_modparam_pio = B43_PIO_DEFAULT;
> +module_param_named(pio, b43_modparam_pio, int, 0644);
> +MODULE_PARM_DESC(pio, "Use PIO accesses by default: 0=DMA, 1=PIO");
> +
> int b43_modparam_verbose = B43_VERBOSITY_DEFAULT;
> module_param_named(verbose, b43_modparam_verbose, int, 0644);
> MODULE_PARM_DESC(verbose, "Log message verbosity: 0=error, 1=warn, 2=info(default), 3=debug");
> @@ -1795,6 +1799,9 @@ static void b43_do_interrupt_thread(struct b43_wldev *dev)
> "on your system. Please use PIO instead.\n");
> b43err(dev->wl, "CONFIG_B43_FORCE_PIO must be set in "
> "your kernel configuration.\n");
> + /* Fall back to PIO transfers if we get fatal DMA errors! */
> + dev->use_pio = 1;
> + b43_controller_restart(dev, "DMA error");
> return;
> }
> if (merged_dma_reason & B43_DMAIRQ_NONFATALMASK) {
> @@ -4360,7 +4367,7 @@ static int b43_wireless_core_init(struct b43_wldev *dev)
>
> if ((dev->dev->bus->bustype == SSB_BUSTYPE_PCMCIA) ||
> (dev->dev->bus->bustype == SSB_BUSTYPE_SDIO) ||
> - B43_FORCE_PIO) {
> + dev->use_pio) {
> dev->__using_pio_transfers = 1;
> err = b43_pio_init(dev);
> } else {
> @@ -4830,6 +4837,7 @@ static int b43_one_core_attach(struct ssb_device *dev, struct b43_wl *wl)
> if (!wldev)
> goto out;
>
> + wldev->use_pio = b43_modparam_pio;
> wldev->dev = dev;
> wldev->wl = wl;
> b43_set_status(wldev, B43_STAT_UNINIT);
Well, my original plan was to get rid of controller_restart and not add yet
another user of it, because it is extremely broken and racy. The locking in the
whole driver is completely braindead due to the mere existence of this function.
I'd rather appreciate that somebody who owns such a device and can reproduce the bug
would do some _real_ debugging on the issue instead.
--
Greetings, Michael.
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