<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/gpu, branch v4.14.145</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>drm/mediatek: mtk_drm_drv.c: Add of_node_put() before goto</title>
<updated>2019-09-19T07:08:08+00:00</updated>
<author>
<name>Nishka Dasgupta</name>
<email>nishkadg.linux@gmail.com</email>
</author>
<published>2019-07-06T13:30:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=9251e586a1dffd9f964a2a770f6dc82d175ddcb5'/>
<id>9251e586a1dffd9f964a2a770f6dc82d175ddcb5</id>
<content type='text'>
commit 165d42c012be69900f0e2f8545626cb9e7d4a832 upstream.

Each iteration of for_each_child_of_node puts the previous
node, but in the case of a goto from the middle of the loop, there is
no put, thus causing a memory leak. Hence add an of_node_put before the
goto in two places.
Issue found with Coccinelle.

Fixes: 119f5173628a (drm/mediatek: Add DRM Driver for Mediatek SoC MT8173)

Signed-off-by: Nishka Dasgupta &lt;nishkadg.linux@gmail.com&gt;
Signed-off-by: CK Hu &lt;ck.hu@mediatek.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 165d42c012be69900f0e2f8545626cb9e7d4a832 upstream.

Each iteration of for_each_child_of_node puts the previous
node, but in the case of a goto from the middle of the loop, there is
no put, thus causing a memory leak. Hence add an of_node_put before the
goto in two places.
Issue found with Coccinelle.

Fixes: 119f5173628a (drm/mediatek: Add DRM Driver for Mediatek SoC MT8173)

Signed-off-by: Nishka Dasgupta &lt;nishkadg.linux@gmail.com&gt;
Signed-off-by: CK Hu &lt;ck.hu@mediatek.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/meson: Add support for XBGR8888 &amp; ABGR8888 formats</title>
<updated>2019-09-19T07:08:05+00:00</updated>
<author>
<name>Neil Armstrong</name>
<email>narmstrong@baylibre.com</email>
</author>
<published>2019-04-29T07:52:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=73cacb9bb9ed76ff1bf10688adea5dfc19849d37'/>
<id>73cacb9bb9ed76ff1bf10688adea5dfc19849d37</id>
<content type='text'>
commit 5ffff4415f9eeae834960226770963e2947e17eb upstream.

Add missing XBGR8888 &amp; ABGR8888 formats variants from the primary plane.

Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
Signed-off-by: Neil Armstrong &lt;narmstrong@baylibre.com&gt;
Reviewed-by: Kevin Hilman &lt;khilman@baylibre.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190429075238.7884-1-narmstrong@baylibre.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5ffff4415f9eeae834960226770963e2947e17eb upstream.

Add missing XBGR8888 &amp; ABGR8888 formats variants from the primary plane.

Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
Signed-off-by: Neil Armstrong &lt;narmstrong@baylibre.com&gt;
Reviewed-by: Kevin Hilman &lt;khilman@baylibre.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190429075238.7884-1-narmstrong@baylibre.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/vmwgfx: Fix double free in vmw_recv_msg()</title>
<updated>2019-09-16T06:20:43+00:00</updated>
<author>
<name>Dan Carpenter</name>
<email>dan.carpenter@oracle.com</email>
</author>
<published>2019-08-15T08:30:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=1fab51be84fdcae2287f34caad1a3828e056c9c1'/>
<id>1fab51be84fdcae2287f34caad1a3828e056c9c1</id>
<content type='text'>
commit 08b0c891605acf727e43e3e03a25857d3e789b61 upstream.

We recently added a kfree() after the end of the loop:

	if (retries == RETRIES) {
		kfree(reply);
		return -EINVAL;
	}

There are two problems.  First the test is wrong and because retries
equals RETRIES if we succeed on the last iteration through the loop.
Second if we fail on the last iteration through the loop then the kfree
is a double free.

When you're reading this code, please note the break statement at the
end of the while loop.  This patch changes the loop so that if it's not
successful then "reply" is NULL and we can test for that afterward.

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: 6b7c3b86f0b6 ("drm/vmwgfx: fix memory leak when too many retries have occurred")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Reviewed-by: Thomas Hellstrom &lt;thellstrom@vmware.com&gt;
Signed-off-by: Thomas Hellstrom &lt;thellstrom@vmware.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 08b0c891605acf727e43e3e03a25857d3e789b61 upstream.

We recently added a kfree() after the end of the loop:

	if (retries == RETRIES) {
		kfree(reply);
		return -EINVAL;
	}

There are two problems.  First the test is wrong and because retries
equals RETRIES if we succeed on the last iteration through the loop.
Second if we fail on the last iteration through the loop then the kfree
is a double free.

When you're reading this code, please note the break statement at the
end of the while loop.  This patch changes the loop so that if it's not
successful then "reply" is NULL and we can test for that afterward.

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: 6b7c3b86f0b6 ("drm/vmwgfx: fix memory leak when too many retries have occurred")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Reviewed-by: Thomas Hellstrom &lt;thellstrom@vmware.com&gt;
Signed-off-by: Thomas Hellstrom &lt;thellstrom@vmware.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/mediatek: set DMA max segment size</title>
<updated>2019-09-10T09:32:14+00:00</updated>
<author>
<name>Alexandre Courbot</name>
<email>acourbot@chromium.org</email>
</author>
<published>2019-07-29T05:33:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=91910cc0016578a0d9c181d2bb6f7806a07dbf73'/>
<id>91910cc0016578a0d9c181d2bb6f7806a07dbf73</id>
<content type='text'>
[ Upstream commit 070955558e820b9a89c570b91b1f21762f62b288 ]

This driver requires imported PRIME buffers to appear contiguously in
its IO address space. Make sure this is the case by setting the maximum
DMA segment size to a more suitable value than the default 64KB.

Signed-off-by: Alexandre Courbot &lt;acourbot@chromium.org&gt;
Reviewed-by: Tomasz Figa &lt;tfiga@chromium.org&gt;
Signed-off-by: CK Hu &lt;ck.hu@mediatek.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 070955558e820b9a89c570b91b1f21762f62b288 ]

This driver requires imported PRIME buffers to appear contiguously in
its IO address space. Make sure this is the case by setting the maximum
DMA segment size to a more suitable value than the default 64KB.

Signed-off-by: Alexandre Courbot &lt;acourbot@chromium.org&gt;
Reviewed-by: Tomasz Figa &lt;tfiga@chromium.org&gt;
Signed-off-by: CK Hu &lt;ck.hu@mediatek.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/mediatek: use correct device to import PRIME buffers</title>
<updated>2019-09-10T09:32:14+00:00</updated>
<author>
<name>Alexandre Courbot</name>
<email>acourbot@chromium.org</email>
</author>
<published>2019-07-29T05:33:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=5655a71f8252f7681445df58701b9a93b3860269'/>
<id>5655a71f8252f7681445df58701b9a93b3860269</id>
<content type='text'>
[ Upstream commit 4c6f3196e6ea111c456c6086dc3f57d4706b0b2d ]

PRIME buffers should be imported using the DMA device. To this end, use
a custom import function that mimics drm_gem_prime_import_dev(), but
passes the correct device.

Fixes: 119f5173628aa ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Signed-off-by: Alexandre Courbot &lt;acourbot@chromium.org&gt;
Signed-off-by: CK Hu &lt;ck.hu@mediatek.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 4c6f3196e6ea111c456c6086dc3f57d4706b0b2d ]

PRIME buffers should be imported using the DMA device. To this end, use
a custom import function that mimics drm_gem_prime_import_dev(), but
passes the correct device.

Fixes: 119f5173628aa ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Signed-off-by: Alexandre Courbot &lt;acourbot@chromium.org&gt;
Signed-off-by: CK Hu &lt;ck.hu@mediatek.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/i915: Don't deballoon unused ggtt drm_mm_node in linux guest</title>
<updated>2019-09-06T08:20:59+00:00</updated>
<author>
<name>Xiong Zhang</name>
<email>xiong.y.zhang@intel.com</email>
</author>
<published>2019-08-20T05:46:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=fdd176296f35c8810bb45b8a8c1e5df93f01fbd4'/>
<id>fdd176296f35c8810bb45b8a8c1e5df93f01fbd4</id>
<content type='text'>
commit 0a3dfbb5cd9033752639ef33e319c2f2863c713a upstream.

The following call trace may exist in linux guest dmesg when guest i915
driver is unloaded.
[   90.776610] [drm:vgt_deballoon_space.isra.0 [i915]] deballoon space: range [0x0 - 0x0] 0 KiB.
[   90.776621] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c0
[   90.776691] IP: drm_mm_remove_node+0x4d/0x320 [drm]
[   90.776718] PGD 800000012c7d0067 P4D 800000012c7d0067 PUD 138e4c067 PMD 0
[   90.777091] task: ffff9adab60f2f00 task.stack: ffffaf39c0fe0000
[   90.777142] RIP: 0010:drm_mm_remove_node+0x4d/0x320 [drm]
[   90.777573] Call Trace:
[   90.777653]  intel_vgt_deballoon+0x4c/0x60 [i915]
[   90.777729]  i915_ggtt_cleanup_hw+0x121/0x190 [i915]
[   90.777792]  i915_driver_unload+0x145/0x180 [i915]
[   90.777856]  i915_pci_remove+0x15/0x20 [i915]
[   90.777890]  pci_device_remove+0x3b/0xc0
[   90.777916]  device_release_driver_internal+0x157/0x220
[   90.777945]  driver_detach+0x39/0x70
[   90.777967]  bus_remove_driver+0x51/0xd0
[   90.777990]  pci_unregister_driver+0x23/0x90
[   90.778019]  SyS_delete_module+0x1da/0x240
[   90.778045]  entry_SYSCALL_64_fastpath+0x24/0x87
[   90.778072] RIP: 0033:0x7f34312af067
[   90.778092] RSP: 002b:00007ffdea3da0d8 EFLAGS: 00000206
[   90.778297] RIP: drm_mm_remove_node+0x4d/0x320 [drm] RSP: ffffaf39c0fe3dc0
[   90.778344] ---[ end trace f4b1bc8305fc59dd ]---

Four drm_mm_node are used to reserve guest ggtt space, but some of them
may be skipped and not initialised due to space constraints in
intel_vgt_balloon(). If drm_mm_remove_node() is called with
uninitialized drm_mm_node, the above call trace occurs.

This patch check drm_mm_node's validity before calling
drm_mm_remove_node().

Fixes: ff8f797557c7("drm/i915: return the correct usable aperture size under gvt environment")
Cc: stable@vger.kernel.org
Signed-off-by: Xiong Zhang &lt;xiong.y.zhang@intel.com&gt;
Acked-by: Zhenyu Wang &lt;zhenyuw@linux.intel.com&gt;
Reviewed-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/1566279978-9659-1-git-send-email-xiong.y.zhang@intel.com
(cherry picked from commit 4776f3529d6b1e47f02904ad1d264d25ea22b27b)
Signed-off-by: Jani Nikula &lt;jani.nikula@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 0a3dfbb5cd9033752639ef33e319c2f2863c713a upstream.

The following call trace may exist in linux guest dmesg when guest i915
driver is unloaded.
[   90.776610] [drm:vgt_deballoon_space.isra.0 [i915]] deballoon space: range [0x0 - 0x0] 0 KiB.
[   90.776621] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c0
[   90.776691] IP: drm_mm_remove_node+0x4d/0x320 [drm]
[   90.776718] PGD 800000012c7d0067 P4D 800000012c7d0067 PUD 138e4c067 PMD 0
[   90.777091] task: ffff9adab60f2f00 task.stack: ffffaf39c0fe0000
[   90.777142] RIP: 0010:drm_mm_remove_node+0x4d/0x320 [drm]
[   90.777573] Call Trace:
[   90.777653]  intel_vgt_deballoon+0x4c/0x60 [i915]
[   90.777729]  i915_ggtt_cleanup_hw+0x121/0x190 [i915]
[   90.777792]  i915_driver_unload+0x145/0x180 [i915]
[   90.777856]  i915_pci_remove+0x15/0x20 [i915]
[   90.777890]  pci_device_remove+0x3b/0xc0
[   90.777916]  device_release_driver_internal+0x157/0x220
[   90.777945]  driver_detach+0x39/0x70
[   90.777967]  bus_remove_driver+0x51/0xd0
[   90.777990]  pci_unregister_driver+0x23/0x90
[   90.778019]  SyS_delete_module+0x1da/0x240
[   90.778045]  entry_SYSCALL_64_fastpath+0x24/0x87
[   90.778072] RIP: 0033:0x7f34312af067
[   90.778092] RSP: 002b:00007ffdea3da0d8 EFLAGS: 00000206
[   90.778297] RIP: drm_mm_remove_node+0x4d/0x320 [drm] RSP: ffffaf39c0fe3dc0
[   90.778344] ---[ end trace f4b1bc8305fc59dd ]---

Four drm_mm_node are used to reserve guest ggtt space, but some of them
may be skipped and not initialised due to space constraints in
intel_vgt_balloon(). If drm_mm_remove_node() is called with
uninitialized drm_mm_node, the above call trace occurs.

This patch check drm_mm_node's validity before calling
drm_mm_remove_node().

Fixes: ff8f797557c7("drm/i915: return the correct usable aperture size under gvt environment")
Cc: stable@vger.kernel.org
Signed-off-by: Xiong Zhang &lt;xiong.y.zhang@intel.com&gt;
Acked-by: Zhenyu Wang &lt;zhenyuw@linux.intel.com&gt;
Reviewed-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/1566279978-9659-1-git-send-email-xiong.y.zhang@intel.com
(cherry picked from commit 4776f3529d6b1e47f02904ad1d264d25ea22b27b)
Signed-off-by: Jani Nikula &lt;jani.nikula@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/tilcdc: Register cpufreq notifier after we have initialized crtc</title>
<updated>2019-09-06T08:20:49+00:00</updated>
<author>
<name>Jyri Sarha</name>
<email>jsarha@ti.com</email>
</author>
<published>2018-12-12T17:26:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=0d9b9e89ae5a1aa20141fe41c3709149113c4b02'/>
<id>0d9b9e89ae5a1aa20141fe41c3709149113c4b02</id>
<content type='text'>
[ Upstream commit 432973fd3a20102840d5f7e61af9f1a03c217a4c ]

Register cpufreq notifier after we have initialized the crtc and
unregister it before we remove the ctrc. Receiving a cpufreq notify
without crtc causes a crash.

Reported-by: Peter Ujfalusi &lt;peter.ujfalusi@ti.com&gt;
Signed-off-by: Jyri Sarha &lt;jsarha@ti.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 432973fd3a20102840d5f7e61af9f1a03c217a4c ]

Register cpufreq notifier after we have initialized the crtc and
unregister it before we remove the ctrc. Receiving a cpufreq notify
without crtc causes a crash.

Reported-by: Peter Ujfalusi &lt;peter.ujfalusi@ti.com&gt;
Signed-off-by: Jyri Sarha &lt;jsarha@ti.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/bridge: tfp410: fix memleak in get_modes()</title>
<updated>2019-09-06T08:20:47+00:00</updated>
<author>
<name>Tomi Valkeinen</name>
<email>tomi.valkeinen@ti.com</email>
</author>
<published>2019-06-10T13:57:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=d262e6a81729dcf6f6100bb6b5ae87b19050d5d4'/>
<id>d262e6a81729dcf6f6100bb6b5ae87b19050d5d4</id>
<content type='text'>
[ Upstream commit c08f99c39083ab55a9c93b3e93cef48711294dad ]

We don't free the edid blob allocated by the call to drm_get_edid(),
causing a memleak. Fix this by calling kfree(edid) at the end of the
get_modes().

Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Signed-off-by: Andrzej Hajda &lt;a.hajda@samsung.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190610135739.6077-1-tomi.valkeinen@ti.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit c08f99c39083ab55a9c93b3e93cef48711294dad ]

We don't free the edid blob allocated by the call to drm_get_edid(),
causing a memleak. Fix this by calling kfree(edid) at the end of the
get_modes().

Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Signed-off-by: Andrzej Hajda &lt;a.hajda@samsung.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190610135739.6077-1-tomi.valkeinen@ti.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/ast: Fixed reboot test may cause system hanged</title>
<updated>2019-09-06T08:20:45+00:00</updated>
<author>
<name>Y.C. Chen</name>
<email>yc_chen@aspeedtech.com</email>
</author>
<published>2018-04-11T01:27:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=5938612e6f461ee30ab5ccc416dd609ae1b74b95'/>
<id>5938612e6f461ee30ab5ccc416dd609ae1b74b95</id>
<content type='text'>
[ Upstream commit 05b439711f6ff8700e8660f97a1179650778b9cb ]

There is another thread still access standard VGA I/O while loading drm driver.
Disable standard VGA I/O decode to avoid this issue.

Signed-off-by: Y.C. Chen &lt;yc_chen@aspeedtech.com&gt;
Reviewed-by: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/1523410059-18415-1-git-send-email-yc_chen@aspeedtech.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 05b439711f6ff8700e8660f97a1179650778b9cb ]

There is another thread still access standard VGA I/O while loading drm driver.
Disable standard VGA I/O decode to avoid this issue.

Signed-off-by: Y.C. Chen &lt;yc_chen@aspeedtech.com&gt;
Reviewed-by: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/1523410059-18415-1-git-send-email-yc_chen@aspeedtech.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/nouveau: Don't retry infinitely when receiving no data on i2c over AUX</title>
<updated>2019-08-29T06:26:42+00:00</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2019-07-25T19:40:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=8ba408f45ee01c3871248d0c8fcb80bdb21ea4fe'/>
<id>8ba408f45ee01c3871248d0c8fcb80bdb21ea4fe</id>
<content type='text'>
commit c358ebf59634f06d8ed176da651ec150df3c8686 upstream.

While I had thought I had fixed this issue in:

commit 342406e4fbba ("drm/nouveau/i2c: Disable i2c bus access after
-&gt;fini()")

It turns out that while I did fix the error messages I was seeing on my
P50 when trying to access i2c busses with the GPU in runtime suspend, I
accidentally had missed one important detail that was mentioned on the
bug report this commit was supposed to fix: that the CPU would only lock
up when trying to access i2c busses _on connected devices_ _while the
GPU is not in runtime suspend_. Whoops. That definitely explains why I
was not able to get my machine to hang with i2c bus interactions until
now, as plugging my P50 into it's dock with an HDMI monitor connected
allowed me to finally reproduce this locally.

Now that I have managed to reproduce this issue properly, it looks like
the problem is much simpler then it looks. It turns out that some
connected devices, such as MST laptop docks, will actually ACK i2c reads
even if no data was actually read:

[  275.063043] nouveau 0000:01:00.0: i2c: aux 000a: 1: 0000004c 1
[  275.063447] nouveau 0000:01:00.0: i2c: aux 000a: 00 01101000 10040000
[  275.063759] nouveau 0000:01:00.0: i2c: aux 000a: rd 00000001
[  275.064024] nouveau 0000:01:00.0: i2c: aux 000a: rd 00000000
[  275.064285] nouveau 0000:01:00.0: i2c: aux 000a: rd 00000000
[  275.064594] nouveau 0000:01:00.0: i2c: aux 000a: rd 00000000

Because we don't handle the situation of i2c ack without any data, we
end up entering an infinite loop in nvkm_i2c_aux_i2c_xfer() since the
value of cnt always remains at 0. This finally properly explains how
this could result in a CPU hang like the ones observed in the
aforementioned commit.

So, fix this by retrying transactions if no data is written or received,
and give up and fail the transaction if we continue to not write or
receive any data after 32 retries.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c358ebf59634f06d8ed176da651ec150df3c8686 upstream.

While I had thought I had fixed this issue in:

commit 342406e4fbba ("drm/nouveau/i2c: Disable i2c bus access after
-&gt;fini()")

It turns out that while I did fix the error messages I was seeing on my
P50 when trying to access i2c busses with the GPU in runtime suspend, I
accidentally had missed one important detail that was mentioned on the
bug report this commit was supposed to fix: that the CPU would only lock
up when trying to access i2c busses _on connected devices_ _while the
GPU is not in runtime suspend_. Whoops. That definitely explains why I
was not able to get my machine to hang with i2c bus interactions until
now, as plugging my P50 into it's dock with an HDMI monitor connected
allowed me to finally reproduce this locally.

Now that I have managed to reproduce this issue properly, it looks like
the problem is much simpler then it looks. It turns out that some
connected devices, such as MST laptop docks, will actually ACK i2c reads
even if no data was actually read:

[  275.063043] nouveau 0000:01:00.0: i2c: aux 000a: 1: 0000004c 1
[  275.063447] nouveau 0000:01:00.0: i2c: aux 000a: 00 01101000 10040000
[  275.063759] nouveau 0000:01:00.0: i2c: aux 000a: rd 00000001
[  275.064024] nouveau 0000:01:00.0: i2c: aux 000a: rd 00000000
[  275.064285] nouveau 0000:01:00.0: i2c: aux 000a: rd 00000000
[  275.064594] nouveau 0000:01:00.0: i2c: aux 000a: rd 00000000

Because we don't handle the situation of i2c ack without any data, we
end up entering an infinite loop in nvkm_i2c_aux_i2c_xfer() since the
value of cnt always remains at 0. This finally properly explains how
this could result in a CPU hang like the ones observed in the
aforementioned commit.

So, fix this by retrying transactions if no data is written or received,
and give up and fail the transaction if we continue to not write or
receive any data after 32 retries.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
