/* * sound/oss/pas2_midi.c * * The low level driver for the PAS Midi Interface. */ /* * Copyright (C) by Hannu Savolainen 1993-1997 * * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL) * Version 2 (June 1991). See the "COPYING" file distributed with this software * for more info. * * Bartlomiej Zolnierkiewicz : Added __init to pas_init_mixer() */ #include #include #include "sound_config.h" #include "pas2.h" extern spinlock_t pas_lock; static int midi_busy, input_opened; static int my_dev; int pas2_mididev=-1; static unsigned char tmp_queue[256]; static volatile int qlen; static volatile unsigned char qhead, qtail; static void (*midi_input_intr) (int dev, unsigned char data); static int pas_midi_open(int dev, int mode, void (*input) (int dev, unsigned char data), void (*output) (int dev) ) { int err; unsigned long flags; unsigned char ctrl; if (midi_busy) return -EBUSY; /* * Reset input and output FIFO pointers */ pas_write(0x20 | 0x40, 0x178b); spin_lock_irqsave(&pas_lock, flags); if ((err = pas_set_intr(0x10)) < 0) { spin_unlock_irqrestore(&pas_lock, flags); return err; } /* * Enable input available and output FIFO empty interrupts */ ctrl = 0; input_opened = 0; midi_input_intr = input; if (mode == OPEN_READ || mode == OPEN_READWRITE) { ctrl |= 0x04; /* Enable input */ input_opened = 1; } if (mode == OPEN_WRITE || mode == OPEN_READWRITE) { ctrl |= 0x08 | 0x10; /* Enable output */ } pas_write(ctrl, 0x178b); /* * Acknowledge any pending interrupts */ pas_write(0xff, 0x1B88); spin_unlock_irqrestore(&pas_lock, flags); midi_busy = 1; qlen = qhead = qtail = 0; return 0; } static void pas_midi_close(int dev) { /* * Reset FIFO pointers, disable intrs */ pas_write(0x20 | 0x40, 0x178b); pas_remove_intr(0x10); midi_busy = 0; } static int dump_to_midi(unsigned char midi_byte) { int fifo_space, x; fifo_space = ((x = pas_read(0x1B89)) >> 4) & 0x0f; /* * The MIDI FIFO space register and it's documentation is nonunderstandable. * There seem to be no way to differentiate between buffer full and buffer * empty situations. For this reason we don't never write the buffer * completely full. In this way we can assume that 0 (or is it 15) * means that the buffer is empty. */ if (fifo_space < 2 && fifo_space != 0) /* Full (almost) */ return 0; /* Ask upper layers to retry after some time */ pas_write(midi_byte, 0x178A); return 1; } static int pas_midi_out(int dev, unsigned char midi_byte) { unsigned long flags; /* * Drain the local queue first */ spin_lock_irqsave(&pas_lock, flags); while (qlen && dump_to_midi(tmp_queue[qhead])) { qlen--; qhead++; } spin_unlock_irqrestore(&pas_lock, flags); /* * Output the byte if the local queue is empty. */ if (!qlen) if (dump_to_midi(midi_byte)) return 1; /* * Put to the local queue */ if (qlen >= 256) return 0; /* Local queue full */ spin_lock_irqsave(&pas_lock, flags); tmp_queue[qtail] = midi_byte; qlen++; qtail++; spin_unlock_irqrestore(&pas_lock, flags); return 1; } static int pas_midi_start_read(int dev) { return 0; } static int pas_midi_end_read(int dev) { return 0; } static void pas_midi_kick(int dev) { } static int pas_buffer_status(int dev) { return qlen; } #define MIDI_SYNTH_NAME "Pro Audio Spectrum Midi" #define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT #include "midi_synth.h" static struct midi_operations pas_midi_operations = { .owner = THIS_MODULE, .info = {"Pro Audio Spectrum", 0, 0, SNDCARD_PAS}, .converter = &std_midi_synth, .in_info = {0}, .open = pas_midi_open, .close = pas_midi_close, .outputc = pas_midi_out, .start_read = pas_midi_start_read, .end_read = pas_midi_end_read, .kick = pas_midi_kick, .buffer_status = pas_buffer_status, }; void __init pas_midi_init(void) { int dev = sound_alloc_mididev(); if (dev == -1) { printk(KERN_WARNING "pas_midi_init: Too many midi devices detected\n"); return; } std_midi_synth.midi_dev = my_dev = dev; midi_devs[dev] = &pas_midi_operations; pas2_mididev = dev; sequencer_init(); } void pas_midi_interrupt(void) { unsigned char stat; int i, incount; stat = pas_read(0x1B88); if (stat & 0x04) /* Input data available */ { incount = pas_read(0x1B89) & 0x0f; /* Input FIFO size */ if (!incount) incount = 16; for (i = 0; i < incount; i++) if (input_opened) { midi_input_intr(my_dev, pas_read(0x178A)); } else pas_read(0x178A); /* Flush */ } if (stat & (0x08 | 0x10)) { spin_lock(&pas_lock);/* called in irq context */ while (qlen && dump_to_midi(tmp_queue[qhead])) { qlen--; qhead++; } spin_unlock(&pas_lock); } if (stat & 0x40) { printk(KERN_WARNING "MIDI output overrun %x,%x\n", pas_read(0x1B89), stat); } pas_write(stat, 0x1B88); /* Acknowledge interrupts */ } :06 -0800 committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800 commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch) tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /sound/pci/asihpi parent2c5d9555d6d937966d79d4c6529a5f7b9206e405 (diff)
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
I've seen this trigger twice now, where the i915_gem_object_to_ggtt() call in intel_unpin_fb_obj() returns NULL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'sound/pci/asihpi')