From 187cfc439f7b1a7c91ff72d561b2a7c9c0b83431 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 9 Mar 2009 14:36:15 +0000 Subject: hvc_console: Remove tty->low_latency on pseries backends The hvcs and hvsi backends both set tty->low_latency to one, along with more or less scary comments regarding bugs or races that would happen if not doing so. However, they also both call tty_flip_buffer_push() in conexts where it's illegal to do so since some recent tty changes (or at least it may have been illegal always but it nows blows) when low_latency is set (ie, hard interrupt or with spinlock held and irqs disabled). This removes the setting for now to get them back to working condition, we'll have to address the races described in the comments separately if they are still an issue (some of this might have been fixed already). Signed-off-by: Benjamin Herrenschmidt --- drivers/char/hvcs.c | 9 --------- drivers/char/hvsi.c | 1 - 2 files changed, 10 deletions(-) (limited to 'drivers') diff --git a/drivers/char/hvcs.c b/drivers/char/hvcs.c index 6e6eb445d374..c76bccf5354d 100644 --- a/drivers/char/hvcs.c +++ b/drivers/char/hvcs.c @@ -1139,15 +1139,6 @@ static int hvcs_open(struct tty_struct *tty, struct file *filp) hvcsd->tty = tty; tty->driver_data = hvcsd; - /* - * Set this driver to low latency so that we actually have a chance at - * catching a throttled TTY after we flip_buffer_push. Otherwise the - * flush_to_async may not execute until after the kernel_thread has - * yielded and resumed the next flip_buffer_push resulting in data - * loss. - */ - tty->low_latency = 1; - memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); /* diff --git a/drivers/char/hvsi.c b/drivers/char/hvsi.c index 406f8742a260..2989056a9e39 100644 --- a/drivers/char/hvsi.c +++ b/drivers/char/hvsi.c @@ -810,7 +810,6 @@ static int hvsi_open(struct tty_struct *tty, struct file *filp) hp = &hvsi_ports[line]; tty->driver_data = hp; - tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */ mb(); if (hp->state == HVSI_FSP_DIED) -- cgit v1.2.3 From d801cec70d69d2d4121e133edd5c3237fe0e0078 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 11 Mar 2009 10:45:17 +1100 Subject: radeonfb/aty128fb: Disable broken early resume hook for PowerBooks radeonfb and aty128fb have a special hook called by the PowerMac platform code very very early on resume from sleep to bring the screen back. This is useful for debugging wakup problems, but unfortunately, this also became a source of problems of its own. The hook is called extremely early, with interrupts still off, and the code path involved with that code nowadays rely on things like taking mutexes, GFP_KERNEL allocations, etc... In addition, the driver now relies on the PCI core to restore the standard config space before calling resume which doesn't happen with this early code path. I'm keeping the code in but commented out along with a fixup call to pci_restore_state(). The reason is that I still want to make it easy to re-enable temporarily to track wake up problems, and it's possible that I can revive it at some stage if we make sleeping things save to call in early resume using a system state. In the meantime, this should fix several reported regressions. Signed-off-by: Benjamin Herrenschmidt --- drivers/video/aty/aty128fb.c | 10 +++++++++- drivers/video/aty/radeon_pm.c | 10 +++++++++- 2 files changed, 18 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/video/aty/aty128fb.c b/drivers/video/aty/aty128fb.c index 2181ce4d7ebd..35e8eb02b9e9 100644 --- a/drivers/video/aty/aty128fb.c +++ b/drivers/video/aty/aty128fb.c @@ -1853,13 +1853,14 @@ static void aty128_bl_exit(struct backlight_device *bd) * Initialisation */ -#ifdef CONFIG_PPC_PMAC +#ifdef CONFIG_PPC_PMAC__disabled static void aty128_early_resume(void *data) { struct aty128fb_par *par = data; if (try_acquire_console_sem()) return; + pci_restore_state(par->pdev); aty128_do_resume(par->pdev); release_console_sem(); } @@ -1907,7 +1908,14 @@ static int __devinit aty128_init(struct pci_dev *pdev, const struct pci_device_i /* Indicate sleep capability */ if (par->chip_gen == rage_M3) { pmac_call_feature(PMAC_FTR_DEVICE_CAN_WAKE, NULL, 0, 1); +#if 0 /* Disable the early video resume hack for now as it's causing problems, among + * others we now rely on the PCI core restoring the config space for us, which + * isn't the case with that hack, and that code path causes various things to + * be called with interrupts off while they shouldn't. I'm leaving the code in + * as it can be useful for debugging purposes + */ pmac_set_early_video_resume(aty128_early_resume, par); +#endif } /* Find default mode */ diff --git a/drivers/video/aty/radeon_pm.c b/drivers/video/aty/radeon_pm.c index ca5f0dc28546..81603f85e17e 100644 --- a/drivers/video/aty/radeon_pm.c +++ b/drivers/video/aty/radeon_pm.c @@ -2762,12 +2762,13 @@ int radeonfb_pci_resume(struct pci_dev *pdev) return rc; } -#ifdef CONFIG_PPC_OF +#ifdef CONFIG_PPC_OF__disabled static void radeonfb_early_resume(void *data) { struct radeonfb_info *rinfo = data; rinfo->no_schedule = 1; + pci_restore_state(rinfo->pdev); radeonfb_pci_resume(rinfo->pdev); rinfo->no_schedule = 0; } @@ -2834,7 +2835,14 @@ void radeonfb_pm_init(struct radeonfb_info *rinfo, int dynclk, int ignore_devlis */ if (rinfo->pm_mode != radeon_pm_none) { pmac_call_feature(PMAC_FTR_DEVICE_CAN_WAKE, rinfo->of_node, 0, 1); +#if 0 /* Disable the early video resume hack for now as it's causing problems, among + * others we now rely on the PCI core restoring the config space for us, which + * isn't the case with that hack, and that code path causes various things to + * be called with interrupts off while they shouldn't. I'm leaving the code in + * as it can be useful for debugging purposes + */ pmac_set_early_video_resume(radeonfb_early_resume, rinfo); +#endif } #if 0 -- cgit v1.2.3