/*
 * Thunderbolt Cactus Ridge driver - control channel and configuration commands
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 */

#ifndef _TB_CFG
#define _TB_CFG

#include "nhi.h"

/* control channel */
struct tb_ctl;

typedef void (*hotplug_cb)(void *data, u64 route, u8 port, bool unplug);

struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, hotplug_cb cb, void *cb_data);
void tb_ctl_start(struct tb_ctl *ctl);
void tb_ctl_stop(struct tb_ctl *ctl);
void tb_ctl_free(struct tb_ctl *ctl);

/* configuration commands */

#define TB_CFG_DEFAULT_TIMEOUT 5000 /* msec */

enum tb_cfg_space {
	TB_CFG_HOPS = 0,
	TB_CFG_PORT = 1,
	TB_CFG_SWITCH = 2,
	TB_CFG_COUNTERS = 3,
};

enum tb_cfg_error {
	TB_CFG_ERROR_PORT_NOT_CONNECTED = 0,
	TB_CFG_ERROR_INVALID_CONFIG_SPACE = 2,
	TB_CFG_ERROR_NO_SUCH_PORT = 4,
	TB_CFG_ERROR_ACK_PLUG_EVENT = 7, /* send as reply to TB_CFG_PKG_EVENT */
	TB_CFG_ERROR_LOOP = 8,
};

struct tb_cfg_result {
	u64 response_route;
	u32 response_port; /*
			    * If err = 1 then this is the port that send the
			    * error.
			    * If err = 0 and if this was a cfg_read/write then
			    * this is the the upstream port of the responding
			    * switch.
			    * Otherwise the field is set to zero.
			    */
	int err; /* negative errors, 0 for success, 1 for tb errors */
	enum tb_cfg_error tb_error; /* valid if err == 1 */
};


int tb_cfg_error(struct tb_ctl *ctl, u64 route, u32 port,
		 enum tb_cfg_error error);
struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route,
				  int timeout_msec);
struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
				     u64 route, u32 port,
				     enum tb_cfg_space space, u32 offset,
				     u32 length, int timeout_msec);
struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, void *buffer,
				      u64 route, u32 port,
				      enum tb_cfg_space space, u32 offset,
				      u32 length, int timeout_msec);
int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
		enum tb_cfg_space space, u32 offset, u32 length);
int tb_cfg_write(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
		 enum tb_cfg_space space, u32 offset, u32 length);
int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route);


#endif
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>include</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/net?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/net/inet_connection_sock.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>inet_connection_sock.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='39cb2c9a316e77f6dfba96c543e55b6672d5a37e'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/net/inet_connection_sock.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/net/inet_connection_sock.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>98fe974ee4e20121253de7f61fc8d01bdb3821c1</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/net/inet_connection_sock.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>include/net/inet_connection_sock.h</a></td></tr>
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<div class='commit-subject'>drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()</div><div class='commit-msg'>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 &lt;daniel.vetter@intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@linux.intel.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>Diffstat</a> (limited to 'include/net/inet_connection_sock.h')</div><table summary='diffstat' class='diffstat'>