/*
 * cec-edid - HDMI Consumer Electronics Control & EDID helpers
 *
 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef _MEDIA_CEC_EDID_H
#define _MEDIA_CEC_EDID_H

#include <linux/types.h>

#define CEC_PHYS_ADDR_INVALID		0xffff
#define cec_phys_addr_exp(pa) \
	((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf

/**
 * cec_get_edid_phys_addr() - find and return the physical address
 *
 * @edid:	pointer to the EDID data
 * @size:	size in bytes of the EDID data
 * @offset:	If not %NULL then the location of the physical address
 *		bytes in the EDID will be returned here. This is set to 0
 *		if there is no physical address found.
 *
 * Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
 */
u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
			   unsigned int *offset);

/**
 * cec_set_edid_phys_addr() - find and set the physical address
 *
 * @edid:	pointer to the EDID data
 * @size:	size in bytes of the EDID data
 * @phys_addr:	the new physical address
 *
 * This function finds the location of the physical address in the EDID
 * and fills in the given physical address and updates the checksum
 * at the end of the EDID block. It does nothing if the EDID doesn't
 * contain a physical address.
 */
void cec_set_edid_phys_addr(u8 *edid, unsigned int size, u16 phys_addr);

/**
 * cec_phys_addr_for_input() - calculate the PA for an input
 *
 * @phys_addr:	the physical address of the parent
 * @input:	the number of the input port, must be between 1 and 15
 *
 * This function calculates a new physical address based on the input
 * port number. For example:
 *
 * PA = 0.0.0.0 and input = 2 becomes 2.0.0.0
 *
 * PA = 3.0.0.0 and input = 1 becomes 3.1.0.0
 *
 * PA = 3.2.1.0 and input = 5 becomes 3.2.1.5
 *
 * PA = 3.2.1.3 and input = 5 becomes f.f.f.f since it maxed out the depth.
 *
 * Return: the new physical address or CEC_PHYS_ADDR_INVALID.
 */
u16 cec_phys_addr_for_input(u16 phys_addr, u8 input);

/**
 * cec_phys_addr_validate() - validate a physical address from an EDID
 *
 * @phys_addr:	the physical address to validate
 * @parent:	if not %NULL, then this is filled with the parents PA.
 * @port:	if not %NULL, then this is filled with the input port.
 *
 * This validates a physical address as read from an EDID. If the
 * PA is invalid (such as 1.0.1.0 since '0' is only allowed at the end),
 * then it will return -EINVAL.
 *
 * The parent PA is passed into %parent and the input port is passed into
 * %port. For example:
 *
 * PA = 0.0.0.0: has parent 0.0.0.0 and input port 0.
 *
 * PA = 1.0.0.0: has parent 0.0.0.0 and input port 1.
 *
 * PA = 3.2.0.0: has parent 3.0.0.0 and input port 2.
 *
 * PA = f.f.f.f: has parent f.f.f.f and input port 0.
 *
 * Return: 0 if the PA is valid, -EINVAL if not.
 */
int cec_phys_addr_validate(u16 phys_addr, u16 *parent, u16 *port);

#endif /* _MEDIA_CEC_EDID_H */
='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/sound/isa/gus/gusextreme.c?h=nds-private-remove&amp;id=62d1086e87223260fcdc49c232d5c2e26ff05721&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
<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/sound/isa/msnd/msnd_classic.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/isa/msnd/msnd_classic.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/sound/isa/msnd/msnd_classic.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>sound/isa/msnd/msnd_classic.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/isa/msnd/msnd_classic.h?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/isa/msnd/msnd_classic.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e&amp;id2=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>diff</a>)</td></tr></table>
<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 'sound/isa/msnd/msnd_classic.h')</div><table summary='diffstat' class='diffstat'>