* Re: [REPOST PATCH] drm/msm: Set dma maximum segment size for mdss
@ 2020-01-21 19:26 ` Rob Clark
0 siblings, 0 replies; 10+ messages in thread
From: Rob Clark @ 2020-01-21 19:26 UTC (permalink / raw)
To: Douglas Anderson
Cc: freedreno, saiprakash.ranjan, David Airlie, linux-arm-msm,
Linux Kernel Mailing List, dri-devel, Stephen Boyd,
Matthias Kaehlcke, Sean Paul, Sean Paul
On Tue, Jan 21, 2020 at 11:19 AM Douglas Anderson <dianders@chromium.org> wrote:
>
> From: Sean Paul <seanpaul@chromium.org>
>
> Turning on CONFIG_DMA_API_DEBUG_SG results in the following error:
>
> [ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer than device claims to support [len=3526656] [max=65536]
> [ 12.089870] WARNING: CPU: 6 PID: 334 at /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301 debug_dma_map_sg+0x1dc/0x318
> [ 12.102655] Modules linked in: joydev
> [ 12.106442] CPU: 6 PID: 334 Comm: frecon Not tainted 4.19.0 #2
> [ 12.112450] Hardware name: Google Cheza (rev3+) (DT)
> [ 12.117566] pstate: 60400009 (nZCv daif +PAN -UAO)
> [ 12.122506] pc : debug_dma_map_sg+0x1dc/0x318
> [ 12.126995] lr : debug_dma_map_sg+0x1dc/0x318
> [ 12.131487] sp : ffffff800cc3ba80
> [ 12.134913] x29: ffffff800cc3ba80 x28: 0000000000000000
> [ 12.140395] x27: 0000000000000004 x26: 0000000000000004
> [ 12.145868] x25: ffffff8008e55b18 x24: 0000000000000000
> [ 12.151337] x23: 00000000ffffffff x22: ffffff800921c000
> [ 12.156809] x21: ffffffc0fa75b080 x20: ffffffc0f7195090
> [ 12.162280] x19: ffffffc0f1c53280 x18: 0000000000000000
> [ 12.167749] x17: 0000000000000000 x16: 0000000000000000
> [ 12.173218] x15: 0000000000000000 x14: 0720072007200720
> [ 12.178689] x13: 0720072007200720 x12: 0720072007200720
> [ 12.184161] x11: 0720072007200720 x10: 0720072007200720
> [ 12.189641] x9 : ffffffc0f1fc6b60 x8 : 0000000000000000
> [ 12.195110] x7 : ffffff8008132ce0 x6 : 0000000000000000
> [ 12.200585] x5 : 0000000000000000 x4 : ffffff8008134734
> [ 12.206058] x3 : ffffff800cc3b830 x2 : ffffffc0f1fc6240
> [ 12.211532] x1 : 25045a74f48a7400 x0 : 25045a74f48a7400
> [ 12.217006] Call trace:
> [ 12.219535] debug_dma_map_sg+0x1dc/0x318
> [ 12.223671] get_pages+0x19c/0x20c
> [ 12.227177] msm_gem_fault+0x64/0xfc
> [ 12.230874] __do_fault+0x3c/0x140
> [ 12.234383] __handle_mm_fault+0x70c/0xdb8
> [ 12.238603] handle_mm_fault+0xac/0xc4
> [ 12.242473] do_page_fault+0x1bc/0x3d4
> [ 12.246342] do_translation_fault+0x54/0x88
> [ 12.250652] do_mem_abort+0x60/0xf0
> [ 12.254250] el0_da+0x20/0x24
> [ 12.257317] irq event stamp: 67260
> [ 12.260828] hardirqs last enabled at (67259): [<ffffff8008132d0c>] console_unlock+0x214/0x608
> [ 12.269693] hardirqs last disabled at (67260): [<ffffff8008080e0c>] do_debug_exception+0x5c/0x178
> [ 12.278820] softirqs last enabled at (67256): [<ffffff8008081664>] __do_softirq+0x4d4/0x520
> [ 12.287510] softirqs last disabled at (67249): [<ffffff80080be574>] irq_exit+0xa8/0x100
> [ 12.295742] ---[ end trace e63cfc40c313ffab ]---
>
> The root of the problem is that the default segment size for sgt is
> (UINT_MAX & PAGE_MASK), and the default segment size for device dma is
> 64K. As such, if you compare the 2, you would deduce that the sg segment
> will overflow the device's capacity. In reality, the hardware can
> accommodate the larger sg segments, it's just not initializing its max
> segment properly. This patch initializes the max segment size for the
> mdss device, which gets rid of that pesky warning.
>
> Reported-by: Stephen Boyd <swboyd@chromium.org>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> Tested-by: Stephen Boyd <swboyd@chromium.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
> This patch has been floating in the ether for over a year [1]. I know
> next to nothing about it, but I'm told it's still useful so I'm
> helpfully reposting it. Please enjoy.
This looks like the right thing to do.. sorry I overlooked the patch
first time around
Reviewed-by: Rob Clark <robdclark@gmail.com>
(since I've already sent PR for msm-next, could we pick this up via drm-misc?)
BR,
-R
>
> [1] https://lore.kernel.org/r/20181106213239.52133-1-sean@poorly.run
>
> drivers/gpu/drm/msm/msm_drv.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index c26219c7a49f..e4b750b0c2d3 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -441,6 +441,14 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
> if (ret)
> goto err_msm_uninit;
>
> + if (!dev->dma_parms) {
> + dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
> + GFP_KERNEL);
> + if (!dev->dma_parms)
> + return -ENOMEM;
> + }
> + dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
> +
> msm_gem_shrinker_init(ddev);
>
> switch (get_mdp_ver(pdev)) {
> --
> 2.25.0.341.g760bfbb309-goog
>
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [REPOST PATCH] drm/msm: Set dma maximum segment size for mdss
2020-01-21 19:26 ` Rob Clark
@ 2020-01-22 14:14 ` Sai Prakash Ranjan
-1 siblings, 0 replies; 10+ messages in thread
From: Sai Prakash Ranjan @ 2020-01-22 14:14 UTC (permalink / raw)
To: Rob Clark, Douglas Anderson
Cc: Matthias Kaehlcke, Stephen Boyd, Sean Paul, Sean Paul,
linux-arm-msm, Linux Kernel Mailing List, dri-devel, David Airlie,
freedreno, Daniel Vetter
Hi,
On 2020-01-22 00:56, Rob Clark wrote:
> On Tue, Jan 21, 2020 at 11:19 AM Douglas Anderson
> <dianders@chromium.org> wrote:
>>
>> From: Sean Paul <seanpaul@chromium.org>
>>
>> Turning on CONFIG_DMA_API_DEBUG_SG results in the following error:
>>
>> [ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer
>> than device claims to support [len=3526656] [max=65536]
>> [ 12.089870] WARNING: CPU: 6 PID: 334 at
>> /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301
>> debug_dma_map_sg+0x1dc/0x318
>> [ 12.102655] Modules linked in: joydev
>> [ 12.106442] CPU: 6 PID: 334 Comm: frecon Not tainted 4.19.0 #2
>> [ 12.112450] Hardware name: Google Cheza (rev3+) (DT)
>> [ 12.117566] pstate: 60400009 (nZCv daif +PAN -UAO)
>> [ 12.122506] pc : debug_dma_map_sg+0x1dc/0x318
>> [ 12.126995] lr : debug_dma_map_sg+0x1dc/0x318
>> [ 12.131487] sp : ffffff800cc3ba80
>> [ 12.134913] x29: ffffff800cc3ba80 x28: 0000000000000000
>> [ 12.140395] x27: 0000000000000004 x26: 0000000000000004
>> [ 12.145868] x25: ffffff8008e55b18 x24: 0000000000000000
>> [ 12.151337] x23: 00000000ffffffff x22: ffffff800921c000
>> [ 12.156809] x21: ffffffc0fa75b080 x20: ffffffc0f7195090
>> [ 12.162280] x19: ffffffc0f1c53280 x18: 0000000000000000
>> [ 12.167749] x17: 0000000000000000 x16: 0000000000000000
>> [ 12.173218] x15: 0000000000000000 x14: 0720072007200720
>> [ 12.178689] x13: 0720072007200720 x12: 0720072007200720
>> [ 12.184161] x11: 0720072007200720 x10: 0720072007200720
>> [ 12.189641] x9 : ffffffc0f1fc6b60 x8 : 0000000000000000
>> [ 12.195110] x7 : ffffff8008132ce0 x6 : 0000000000000000
>> [ 12.200585] x5 : 0000000000000000 x4 : ffffff8008134734
>> [ 12.206058] x3 : ffffff800cc3b830 x2 : ffffffc0f1fc6240
>> [ 12.211532] x1 : 25045a74f48a7400 x0 : 25045a74f48a7400
>> [ 12.217006] Call trace:
>> [ 12.219535] debug_dma_map_sg+0x1dc/0x318
>> [ 12.223671] get_pages+0x19c/0x20c
>> [ 12.227177] msm_gem_fault+0x64/0xfc
>> [ 12.230874] __do_fault+0x3c/0x140
>> [ 12.234383] __handle_mm_fault+0x70c/0xdb8
>> [ 12.238603] handle_mm_fault+0xac/0xc4
>> [ 12.242473] do_page_fault+0x1bc/0x3d4
>> [ 12.246342] do_translation_fault+0x54/0x88
>> [ 12.250652] do_mem_abort+0x60/0xf0
>> [ 12.254250] el0_da+0x20/0x24
>> [ 12.257317] irq event stamp: 67260
>> [ 12.260828] hardirqs last enabled at (67259): [<ffffff8008132d0c>]
>> console_unlock+0x214/0x608
>> [ 12.269693] hardirqs last disabled at (67260): [<ffffff8008080e0c>]
>> do_debug_exception+0x5c/0x178
>> [ 12.278820] softirqs last enabled at (67256): [<ffffff8008081664>]
>> __do_softirq+0x4d4/0x520
>> [ 12.287510] softirqs last disabled at (67249): [<ffffff80080be574>]
>> irq_exit+0xa8/0x100
>> [ 12.295742] ---[ end trace e63cfc40c313ffab ]---
>>
>> The root of the problem is that the default segment size for sgt is
>> (UINT_MAX & PAGE_MASK), and the default segment size for device dma is
>> 64K. As such, if you compare the 2, you would deduce that the sg
>> segment
>> will overflow the device's capacity. In reality, the hardware can
>> accommodate the larger sg segments, it's just not initializing its max
>> segment properly. This patch initializes the max segment size for the
>> mdss device, which gets rid of that pesky warning.
>>
>> Reported-by: Stephen Boyd <swboyd@chromium.org>
>> Signed-off-by: Sean Paul <seanpaul@chromium.org>
>> Tested-by: Stephen Boyd <swboyd@chromium.org>
>> Signed-off-by: Douglas Anderson <dianders@chromium.org>
>> ---
>> This patch has been floating in the ether for over a year [1]. I know
>> next to nothing about it, but I'm told it's still useful so I'm
>> helpfully reposting it. Please enjoy.
>
> This looks like the right thing to do.. sorry I overlooked the patch
> first time around
>
> Reviewed-by: Rob Clark <robdclark@gmail.com>
>
> (since I've already sent PR for msm-next, could we pick this up via
> drm-misc?)
>
This also fixes a similar warning seen on SC7180 during video playback.
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Logs for reference,
localhost ~ # [ 647.100504] ------------[ cut here ]------------
[ 647.105748] DMA-API: msm ae00000.mdss: mapping sg segment longer than
device claims to support [len=524288] [max=65536]
<...snip...>
[ 647.184254] pstate: 60400009 (nZCv daif +PAN -UAO)
[ 647.189211] pc : debug_dma_map_sg+0x1a8/0x2c4
[ 647.193708] lr : debug_dma_map_sg+0x1a8/0x2c4
[ 647.198202] sp : ffffffc010f6ba80
[ 647.201626] x29: ffffffc010f6ba90 x28: 0000000000010000
[ 647.207110] x27: 00000000ffffffff x26: ffffff8174840b80
[ 647.212592] x25: ffffffe9f4fe5000 x24: 0000000000000003
[ 647.218075] x23: ffffff815c223780 x22: ffffff81742d0810
[ 647.223557] x21: 0000000000000003 x20: 0000000000000001
[ 647.229041] x19: 0000000000000001 x18: 0000000000000000
[ 647.234524] x17: 000000000000003c x16: ffffffe9f4444a14
[ 647.240006] x15: 0000000000000006 x14: 0720072007200720
[ 647.245489] x13: 0720072007200720 x12: 0000000000000000
[ 647.250969] x11: 0000000000000000 x10: 0000000000000000
[ 647.256452] x9 : 4be0233cf8ef6200 x8 : 4be0233cf8ef6200
[ 647.261935] x7 : 0720072007200720 x6 : ffffff8175ea0f00
[ 647.267417] x5 : 0000000000000000 x4 : 0000000000000000
[ 647.272898] x3 : 0000000000000000 x2 : ffffff81771d1680
[ 647.278380] x1 : ffffff81771c10c0 x0 : 000000000000006b
[ 647.283863] Call trace:
[ 647.286409] debug_dma_map_sg+0x1a8/0x2c4
[ 647.290569] vb2_dma_sg_dmabuf_ops_map+0x138/0x18c [videobuf2_dma_sg]
[ 647.297215] dma_buf_map_attachment+0x6c/0xb0
[ 647.301724] drm_gem_prime_import_dev+0xa4/0x134
[ 647.306495] drm_gem_prime_fd_to_handle+0xc4/0x194
[ 647.311444] drm_prime_fd_to_handle_ioctl+0x40/0x58
[ 647.316483] drm_ioctl_kernel+0x94/0x10c
[ 647.320538] drm_ioctl+0x264/0x3f8
[ 647.324059] drm_compat_ioctl+0xcc/0xdc
[ 647.328033] __se_compat_sys_ioctl+0x100/0x2074
[ 647.332715] __arm64_compat_sys_ioctl+0x20/0x2c
[ 647.337406] el0_svc_common+0xa4/0x154
[ 647.341279] el0_svc_compat_handler+0x2c/0x38
[ 647.345781] el0_svc_compat+0x8/0x10
[ 647.349474] ---[ end trace 2f188eb70b295b6c ]---
[ 648.282197] ------------[ cut here ]------------
Thanks,
Sai
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [REPOST PATCH] drm/msm: Set dma maximum segment size for mdss
@ 2020-01-22 14:14 ` Sai Prakash Ranjan
0 siblings, 0 replies; 10+ messages in thread
From: Sai Prakash Ranjan @ 2020-01-22 14:14 UTC (permalink / raw)
To: Rob Clark, Douglas Anderson
Cc: freedreno, David Airlie, linux-arm-msm, Linux Kernel Mailing List,
dri-devel, Stephen Boyd, Matthias Kaehlcke, Sean Paul, Sean Paul
Hi,
On 2020-01-22 00:56, Rob Clark wrote:
> On Tue, Jan 21, 2020 at 11:19 AM Douglas Anderson
> <dianders@chromium.org> wrote:
>>
>> From: Sean Paul <seanpaul@chromium.org>
>>
>> Turning on CONFIG_DMA_API_DEBUG_SG results in the following error:
>>
>> [ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer
>> than device claims to support [len=3526656] [max=65536]
>> [ 12.089870] WARNING: CPU: 6 PID: 334 at
>> /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301
>> debug_dma_map_sg+0x1dc/0x318
>> [ 12.102655] Modules linked in: joydev
>> [ 12.106442] CPU: 6 PID: 334 Comm: frecon Not tainted 4.19.0 #2
>> [ 12.112450] Hardware name: Google Cheza (rev3+) (DT)
>> [ 12.117566] pstate: 60400009 (nZCv daif +PAN -UAO)
>> [ 12.122506] pc : debug_dma_map_sg+0x1dc/0x318
>> [ 12.126995] lr : debug_dma_map_sg+0x1dc/0x318
>> [ 12.131487] sp : ffffff800cc3ba80
>> [ 12.134913] x29: ffffff800cc3ba80 x28: 0000000000000000
>> [ 12.140395] x27: 0000000000000004 x26: 0000000000000004
>> [ 12.145868] x25: ffffff8008e55b18 x24: 0000000000000000
>> [ 12.151337] x23: 00000000ffffffff x22: ffffff800921c000
>> [ 12.156809] x21: ffffffc0fa75b080 x20: ffffffc0f7195090
>> [ 12.162280] x19: ffffffc0f1c53280 x18: 0000000000000000
>> [ 12.167749] x17: 0000000000000000 x16: 0000000000000000
>> [ 12.173218] x15: 0000000000000000 x14: 0720072007200720
>> [ 12.178689] x13: 0720072007200720 x12: 0720072007200720
>> [ 12.184161] x11: 0720072007200720 x10: 0720072007200720
>> [ 12.189641] x9 : ffffffc0f1fc6b60 x8 : 0000000000000000
>> [ 12.195110] x7 : ffffff8008132ce0 x6 : 0000000000000000
>> [ 12.200585] x5 : 0000000000000000 x4 : ffffff8008134734
>> [ 12.206058] x3 : ffffff800cc3b830 x2 : ffffffc0f1fc6240
>> [ 12.211532] x1 : 25045a74f48a7400 x0 : 25045a74f48a7400
>> [ 12.217006] Call trace:
>> [ 12.219535] debug_dma_map_sg+0x1dc/0x318
>> [ 12.223671] get_pages+0x19c/0x20c
>> [ 12.227177] msm_gem_fault+0x64/0xfc
>> [ 12.230874] __do_fault+0x3c/0x140
>> [ 12.234383] __handle_mm_fault+0x70c/0xdb8
>> [ 12.238603] handle_mm_fault+0xac/0xc4
>> [ 12.242473] do_page_fault+0x1bc/0x3d4
>> [ 12.246342] do_translation_fault+0x54/0x88
>> [ 12.250652] do_mem_abort+0x60/0xf0
>> [ 12.254250] el0_da+0x20/0x24
>> [ 12.257317] irq event stamp: 67260
>> [ 12.260828] hardirqs last enabled at (67259): [<ffffff8008132d0c>]
>> console_unlock+0x214/0x608
>> [ 12.269693] hardirqs last disabled at (67260): [<ffffff8008080e0c>]
>> do_debug_exception+0x5c/0x178
>> [ 12.278820] softirqs last enabled at (67256): [<ffffff8008081664>]
>> __do_softirq+0x4d4/0x520
>> [ 12.287510] softirqs last disabled at (67249): [<ffffff80080be574>]
>> irq_exit+0xa8/0x100
>> [ 12.295742] ---[ end trace e63cfc40c313ffab ]---
>>
>> The root of the problem is that the default segment size for sgt is
>> (UINT_MAX & PAGE_MASK), and the default segment size for device dma is
>> 64K. As such, if you compare the 2, you would deduce that the sg
>> segment
>> will overflow the device's capacity. In reality, the hardware can
>> accommodate the larger sg segments, it's just not initializing its max
>> segment properly. This patch initializes the max segment size for the
>> mdss device, which gets rid of that pesky warning.
>>
>> Reported-by: Stephen Boyd <swboyd@chromium.org>
>> Signed-off-by: Sean Paul <seanpaul@chromium.org>
>> Tested-by: Stephen Boyd <swboyd@chromium.org>
>> Signed-off-by: Douglas Anderson <dianders@chromium.org>
>> ---
>> This patch has been floating in the ether for over a year [1]. I know
>> next to nothing about it, but I'm told it's still useful so I'm
>> helpfully reposting it. Please enjoy.
>
> This looks like the right thing to do.. sorry I overlooked the patch
> first time around
>
> Reviewed-by: Rob Clark <robdclark@gmail.com>
>
> (since I've already sent PR for msm-next, could we pick this up via
> drm-misc?)
>
This also fixes a similar warning seen on SC7180 during video playback.
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Logs for reference,
localhost ~ # [ 647.100504] ------------[ cut here ]------------
[ 647.105748] DMA-API: msm ae00000.mdss: mapping sg segment longer than
device claims to support [len=524288] [max=65536]
<...snip...>
[ 647.184254] pstate: 60400009 (nZCv daif +PAN -UAO)
[ 647.189211] pc : debug_dma_map_sg+0x1a8/0x2c4
[ 647.193708] lr : debug_dma_map_sg+0x1a8/0x2c4
[ 647.198202] sp : ffffffc010f6ba80
[ 647.201626] x29: ffffffc010f6ba90 x28: 0000000000010000
[ 647.207110] x27: 00000000ffffffff x26: ffffff8174840b80
[ 647.212592] x25: ffffffe9f4fe5000 x24: 0000000000000003
[ 647.218075] x23: ffffff815c223780 x22: ffffff81742d0810
[ 647.223557] x21: 0000000000000003 x20: 0000000000000001
[ 647.229041] x19: 0000000000000001 x18: 0000000000000000
[ 647.234524] x17: 000000000000003c x16: ffffffe9f4444a14
[ 647.240006] x15: 0000000000000006 x14: 0720072007200720
[ 647.245489] x13: 0720072007200720 x12: 0000000000000000
[ 647.250969] x11: 0000000000000000 x10: 0000000000000000
[ 647.256452] x9 : 4be0233cf8ef6200 x8 : 4be0233cf8ef6200
[ 647.261935] x7 : 0720072007200720 x6 : ffffff8175ea0f00
[ 647.267417] x5 : 0000000000000000 x4 : 0000000000000000
[ 647.272898] x3 : 0000000000000000 x2 : ffffff81771d1680
[ 647.278380] x1 : ffffff81771c10c0 x0 : 000000000000006b
[ 647.283863] Call trace:
[ 647.286409] debug_dma_map_sg+0x1a8/0x2c4
[ 647.290569] vb2_dma_sg_dmabuf_ops_map+0x138/0x18c [videobuf2_dma_sg]
[ 647.297215] dma_buf_map_attachment+0x6c/0xb0
[ 647.301724] drm_gem_prime_import_dev+0xa4/0x134
[ 647.306495] drm_gem_prime_fd_to_handle+0xc4/0x194
[ 647.311444] drm_prime_fd_to_handle_ioctl+0x40/0x58
[ 647.316483] drm_ioctl_kernel+0x94/0x10c
[ 647.320538] drm_ioctl+0x264/0x3f8
[ 647.324059] drm_compat_ioctl+0xcc/0xdc
[ 647.328033] __se_compat_sys_ioctl+0x100/0x2074
[ 647.332715] __arm64_compat_sys_ioctl+0x20/0x2c
[ 647.337406] el0_svc_common+0xa4/0x154
[ 647.341279] el0_svc_compat_handler+0x2c/0x38
[ 647.345781] el0_svc_compat+0x8/0x10
[ 647.349474] ---[ end trace 2f188eb70b295b6c ]---
[ 648.282197] ------------[ cut here ]------------
Thanks,
Sai
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [REPOST PATCH] drm/msm: Set dma maximum segment size for mdss
2020-01-21 19:26 ` Rob Clark
@ 2020-01-22 14:51 ` Sean Paul
-1 siblings, 0 replies; 10+ messages in thread
From: Sean Paul @ 2020-01-22 14:51 UTC (permalink / raw)
To: Rob Clark
Cc: Douglas Anderson, saiprakash.ranjan, Matthias Kaehlcke,
Stephen Boyd, Sean Paul, Sean Paul, linux-arm-msm,
Linux Kernel Mailing List, dri-devel, David Airlie, freedreno,
Daniel Vetter
On Tue, Jan 21, 2020 at 11:26:05AM -0800, Rob Clark wrote:
> On Tue, Jan 21, 2020 at 11:19 AM Douglas Anderson <dianders@chromium.org> wrote:
> >
> > From: Sean Paul <seanpaul@chromium.org>
> >
> > Turning on CONFIG_DMA_API_DEBUG_SG results in the following error:
> >
> > [ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer than device claims to support [len=3526656] [max=65536]
> > [ 12.089870] WARNING: CPU: 6 PID: 334 at /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301 debug_dma_map_sg+0x1dc/0x318
> > [ 12.102655] Modules linked in: joydev
> > [ 12.106442] CPU: 6 PID: 334 Comm: frecon Not tainted 4.19.0 #2
> > [ 12.112450] Hardware name: Google Cheza (rev3+) (DT)
> > [ 12.117566] pstate: 60400009 (nZCv daif +PAN -UAO)
> > [ 12.122506] pc : debug_dma_map_sg+0x1dc/0x318
> > [ 12.126995] lr : debug_dma_map_sg+0x1dc/0x318
> > [ 12.131487] sp : ffffff800cc3ba80
> > [ 12.134913] x29: ffffff800cc3ba80 x28: 0000000000000000
> > [ 12.140395] x27: 0000000000000004 x26: 0000000000000004
> > [ 12.145868] x25: ffffff8008e55b18 x24: 0000000000000000
> > [ 12.151337] x23: 00000000ffffffff x22: ffffff800921c000
> > [ 12.156809] x21: ffffffc0fa75b080 x20: ffffffc0f7195090
> > [ 12.162280] x19: ffffffc0f1c53280 x18: 0000000000000000
> > [ 12.167749] x17: 0000000000000000 x16: 0000000000000000
> > [ 12.173218] x15: 0000000000000000 x14: 0720072007200720
> > [ 12.178689] x13: 0720072007200720 x12: 0720072007200720
> > [ 12.184161] x11: 0720072007200720 x10: 0720072007200720
> > [ 12.189641] x9 : ffffffc0f1fc6b60 x8 : 0000000000000000
> > [ 12.195110] x7 : ffffff8008132ce0 x6 : 0000000000000000
> > [ 12.200585] x5 : 0000000000000000 x4 : ffffff8008134734
> > [ 12.206058] x3 : ffffff800cc3b830 x2 : ffffffc0f1fc6240
> > [ 12.211532] x1 : 25045a74f48a7400 x0 : 25045a74f48a7400
> > [ 12.217006] Call trace:
> > [ 12.219535] debug_dma_map_sg+0x1dc/0x318
> > [ 12.223671] get_pages+0x19c/0x20c
> > [ 12.227177] msm_gem_fault+0x64/0xfc
> > [ 12.230874] __do_fault+0x3c/0x140
> > [ 12.234383] __handle_mm_fault+0x70c/0xdb8
> > [ 12.238603] handle_mm_fault+0xac/0xc4
> > [ 12.242473] do_page_fault+0x1bc/0x3d4
> > [ 12.246342] do_translation_fault+0x54/0x88
> > [ 12.250652] do_mem_abort+0x60/0xf0
> > [ 12.254250] el0_da+0x20/0x24
> > [ 12.257317] irq event stamp: 67260
> > [ 12.260828] hardirqs last enabled at (67259): [<ffffff8008132d0c>] console_unlock+0x214/0x608
> > [ 12.269693] hardirqs last disabled at (67260): [<ffffff8008080e0c>] do_debug_exception+0x5c/0x178
> > [ 12.278820] softirqs last enabled at (67256): [<ffffff8008081664>] __do_softirq+0x4d4/0x520
> > [ 12.287510] softirqs last disabled at (67249): [<ffffff80080be574>] irq_exit+0xa8/0x100
> > [ 12.295742] ---[ end trace e63cfc40c313ffab ]---
> >
> > The root of the problem is that the default segment size for sgt is
> > (UINT_MAX & PAGE_MASK), and the default segment size for device dma is
> > 64K. As such, if you compare the 2, you would deduce that the sg segment
> > will overflow the device's capacity. In reality, the hardware can
> > accommodate the larger sg segments, it's just not initializing its max
> > segment properly. This patch initializes the max segment size for the
> > mdss device, which gets rid of that pesky warning.
> >
> > Reported-by: Stephen Boyd <swboyd@chromium.org>
> > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > Tested-by: Stephen Boyd <swboyd@chromium.org>
> > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > ---
> > This patch has been floating in the ether for over a year [1]. I know
> > next to nothing about it, but I'm told it's still useful so I'm
> > helpfully reposting it. Please enjoy.
>
> This looks like the right thing to do.. sorry I overlooked the patch
> first time around
>
> Reviewed-by: Rob Clark <robdclark@gmail.com>
>
> (since I've already sent PR for msm-next, could we pick this up via drm-misc?)
You got it, pushed to drm-misc-next-fixes.
Thanks
Sean
>
> BR,
> -R
>
>
> >
> > [1] https://lore.kernel.org/r/20181106213239.52133-1-sean@poorly.run
> >
> > drivers/gpu/drm/msm/msm_drv.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> > index c26219c7a49f..e4b750b0c2d3 100644
> > --- a/drivers/gpu/drm/msm/msm_drv.c
> > +++ b/drivers/gpu/drm/msm/msm_drv.c
> > @@ -441,6 +441,14 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
> > if (ret)
> > goto err_msm_uninit;
> >
> > + if (!dev->dma_parms) {
> > + dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
> > + GFP_KERNEL);
> > + if (!dev->dma_parms)
> > + return -ENOMEM;
> > + }
> > + dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
> > +
> > msm_gem_shrinker_init(ddev);
> >
> > switch (get_mdp_ver(pdev)) {
> > --
> > 2.25.0.341.g760bfbb309-goog
> >
--
Sean Paul, Software Engineer, Google / Chromium OS
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [REPOST PATCH] drm/msm: Set dma maximum segment size for mdss
@ 2020-01-22 14:51 ` Sean Paul
0 siblings, 0 replies; 10+ messages in thread
From: Sean Paul @ 2020-01-22 14:51 UTC (permalink / raw)
To: Rob Clark
Cc: freedreno, saiprakash.ranjan, David Airlie, linux-arm-msm,
Douglas Anderson, dri-devel, Stephen Boyd, Matthias Kaehlcke,
Sean Paul, Sean Paul, Linux Kernel Mailing List
On Tue, Jan 21, 2020 at 11:26:05AM -0800, Rob Clark wrote:
> On Tue, Jan 21, 2020 at 11:19 AM Douglas Anderson <dianders@chromium.org> wrote:
> >
> > From: Sean Paul <seanpaul@chromium.org>
> >
> > Turning on CONFIG_DMA_API_DEBUG_SG results in the following error:
> >
> > [ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer than device claims to support [len=3526656] [max=65536]
> > [ 12.089870] WARNING: CPU: 6 PID: 334 at /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301 debug_dma_map_sg+0x1dc/0x318
> > [ 12.102655] Modules linked in: joydev
> > [ 12.106442] CPU: 6 PID: 334 Comm: frecon Not tainted 4.19.0 #2
> > [ 12.112450] Hardware name: Google Cheza (rev3+) (DT)
> > [ 12.117566] pstate: 60400009 (nZCv daif +PAN -UAO)
> > [ 12.122506] pc : debug_dma_map_sg+0x1dc/0x318
> > [ 12.126995] lr : debug_dma_map_sg+0x1dc/0x318
> > [ 12.131487] sp : ffffff800cc3ba80
> > [ 12.134913] x29: ffffff800cc3ba80 x28: 0000000000000000
> > [ 12.140395] x27: 0000000000000004 x26: 0000000000000004
> > [ 12.145868] x25: ffffff8008e55b18 x24: 0000000000000000
> > [ 12.151337] x23: 00000000ffffffff x22: ffffff800921c000
> > [ 12.156809] x21: ffffffc0fa75b080 x20: ffffffc0f7195090
> > [ 12.162280] x19: ffffffc0f1c53280 x18: 0000000000000000
> > [ 12.167749] x17: 0000000000000000 x16: 0000000000000000
> > [ 12.173218] x15: 0000000000000000 x14: 0720072007200720
> > [ 12.178689] x13: 0720072007200720 x12: 0720072007200720
> > [ 12.184161] x11: 0720072007200720 x10: 0720072007200720
> > [ 12.189641] x9 : ffffffc0f1fc6b60 x8 : 0000000000000000
> > [ 12.195110] x7 : ffffff8008132ce0 x6 : 0000000000000000
> > [ 12.200585] x5 : 0000000000000000 x4 : ffffff8008134734
> > [ 12.206058] x3 : ffffff800cc3b830 x2 : ffffffc0f1fc6240
> > [ 12.211532] x1 : 25045a74f48a7400 x0 : 25045a74f48a7400
> > [ 12.217006] Call trace:
> > [ 12.219535] debug_dma_map_sg+0x1dc/0x318
> > [ 12.223671] get_pages+0x19c/0x20c
> > [ 12.227177] msm_gem_fault+0x64/0xfc
> > [ 12.230874] __do_fault+0x3c/0x140
> > [ 12.234383] __handle_mm_fault+0x70c/0xdb8
> > [ 12.238603] handle_mm_fault+0xac/0xc4
> > [ 12.242473] do_page_fault+0x1bc/0x3d4
> > [ 12.246342] do_translation_fault+0x54/0x88
> > [ 12.250652] do_mem_abort+0x60/0xf0
> > [ 12.254250] el0_da+0x20/0x24
> > [ 12.257317] irq event stamp: 67260
> > [ 12.260828] hardirqs last enabled at (67259): [<ffffff8008132d0c>] console_unlock+0x214/0x608
> > [ 12.269693] hardirqs last disabled at (67260): [<ffffff8008080e0c>] do_debug_exception+0x5c/0x178
> > [ 12.278820] softirqs last enabled at (67256): [<ffffff8008081664>] __do_softirq+0x4d4/0x520
> > [ 12.287510] softirqs last disabled at (67249): [<ffffff80080be574>] irq_exit+0xa8/0x100
> > [ 12.295742] ---[ end trace e63cfc40c313ffab ]---
> >
> > The root of the problem is that the default segment size for sgt is
> > (UINT_MAX & PAGE_MASK), and the default segment size for device dma is
> > 64K. As such, if you compare the 2, you would deduce that the sg segment
> > will overflow the device's capacity. In reality, the hardware can
> > accommodate the larger sg segments, it's just not initializing its max
> > segment properly. This patch initializes the max segment size for the
> > mdss device, which gets rid of that pesky warning.
> >
> > Reported-by: Stephen Boyd <swboyd@chromium.org>
> > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > Tested-by: Stephen Boyd <swboyd@chromium.org>
> > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > ---
> > This patch has been floating in the ether for over a year [1]. I know
> > next to nothing about it, but I'm told it's still useful so I'm
> > helpfully reposting it. Please enjoy.
>
> This looks like the right thing to do.. sorry I overlooked the patch
> first time around
>
> Reviewed-by: Rob Clark <robdclark@gmail.com>
>
> (since I've already sent PR for msm-next, could we pick this up via drm-misc?)
You got it, pushed to drm-misc-next-fixes.
Thanks
Sean
>
> BR,
> -R
>
>
> >
> > [1] https://lore.kernel.org/r/20181106213239.52133-1-sean@poorly.run
> >
> > drivers/gpu/drm/msm/msm_drv.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> > index c26219c7a49f..e4b750b0c2d3 100644
> > --- a/drivers/gpu/drm/msm/msm_drv.c
> > +++ b/drivers/gpu/drm/msm/msm_drv.c
> > @@ -441,6 +441,14 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
> > if (ret)
> > goto err_msm_uninit;
> >
> > + if (!dev->dma_parms) {
> > + dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
> > + GFP_KERNEL);
> > + if (!dev->dma_parms)
> > + return -ENOMEM;
> > + }
> > + dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
> > +
> > msm_gem_shrinker_init(ddev);
> >
> > switch (get_mdp_ver(pdev)) {
> > --
> > 2.25.0.341.g760bfbb309-goog
> >
--
Sean Paul, Software Engineer, Google / Chromium OS
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [REPOST PATCH] drm/msm: Set dma maximum segment size for mdss
2020-01-22 14:51 ` Sean Paul
@ 2020-01-22 15:43 ` Rob Clark
-1 siblings, 0 replies; 10+ messages in thread
From: Rob Clark @ 2020-01-22 15:43 UTC (permalink / raw)
To: Sean Paul
Cc: Douglas Anderson, saiprakash.ranjan, Matthias Kaehlcke,
Stephen Boyd, Sean Paul, linux-arm-msm, Linux Kernel Mailing List,
dri-devel, David Airlie, freedreno, Daniel Vetter
On Wed, Jan 22, 2020 at 6:51 AM Sean Paul <sean@poorly.run> wrote:
>
> On Tue, Jan 21, 2020 at 11:26:05AM -0800, Rob Clark wrote:
> > On Tue, Jan 21, 2020 at 11:19 AM Douglas Anderson <dianders@chromium.org> wrote:
> > >
> > > From: Sean Paul <seanpaul@chromium.org>
> > >
> > > Turning on CONFIG_DMA_API_DEBUG_SG results in the following error:
> > >
> > > [ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer than device claims to support [len=3526656] [max=65536]
> > > [ 12.089870] WARNING: CPU: 6 PID: 334 at /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301 debug_dma_map_sg+0x1dc/0x318
> > > [ 12.102655] Modules linked in: joydev
> > > [ 12.106442] CPU: 6 PID: 334 Comm: frecon Not tainted 4.19.0 #2
> > > [ 12.112450] Hardware name: Google Cheza (rev3+) (DT)
> > > [ 12.117566] pstate: 60400009 (nZCv daif +PAN -UAO)
> > > [ 12.122506] pc : debug_dma_map_sg+0x1dc/0x318
> > > [ 12.126995] lr : debug_dma_map_sg+0x1dc/0x318
> > > [ 12.131487] sp : ffffff800cc3ba80
> > > [ 12.134913] x29: ffffff800cc3ba80 x28: 0000000000000000
> > > [ 12.140395] x27: 0000000000000004 x26: 0000000000000004
> > > [ 12.145868] x25: ffffff8008e55b18 x24: 0000000000000000
> > > [ 12.151337] x23: 00000000ffffffff x22: ffffff800921c000
> > > [ 12.156809] x21: ffffffc0fa75b080 x20: ffffffc0f7195090
> > > [ 12.162280] x19: ffffffc0f1c53280 x18: 0000000000000000
> > > [ 12.167749] x17: 0000000000000000 x16: 0000000000000000
> > > [ 12.173218] x15: 0000000000000000 x14: 0720072007200720
> > > [ 12.178689] x13: 0720072007200720 x12: 0720072007200720
> > > [ 12.184161] x11: 0720072007200720 x10: 0720072007200720
> > > [ 12.189641] x9 : ffffffc0f1fc6b60 x8 : 0000000000000000
> > > [ 12.195110] x7 : ffffff8008132ce0 x6 : 0000000000000000
> > > [ 12.200585] x5 : 0000000000000000 x4 : ffffff8008134734
> > > [ 12.206058] x3 : ffffff800cc3b830 x2 : ffffffc0f1fc6240
> > > [ 12.211532] x1 : 25045a74f48a7400 x0 : 25045a74f48a7400
> > > [ 12.217006] Call trace:
> > > [ 12.219535] debug_dma_map_sg+0x1dc/0x318
> > > [ 12.223671] get_pages+0x19c/0x20c
> > > [ 12.227177] msm_gem_fault+0x64/0xfc
> > > [ 12.230874] __do_fault+0x3c/0x140
> > > [ 12.234383] __handle_mm_fault+0x70c/0xdb8
> > > [ 12.238603] handle_mm_fault+0xac/0xc4
> > > [ 12.242473] do_page_fault+0x1bc/0x3d4
> > > [ 12.246342] do_translation_fault+0x54/0x88
> > > [ 12.250652] do_mem_abort+0x60/0xf0
> > > [ 12.254250] el0_da+0x20/0x24
> > > [ 12.257317] irq event stamp: 67260
> > > [ 12.260828] hardirqs last enabled at (67259): [<ffffff8008132d0c>] console_unlock+0x214/0x608
> > > [ 12.269693] hardirqs last disabled at (67260): [<ffffff8008080e0c>] do_debug_exception+0x5c/0x178
> > > [ 12.278820] softirqs last enabled at (67256): [<ffffff8008081664>] __do_softirq+0x4d4/0x520
> > > [ 12.287510] softirqs last disabled at (67249): [<ffffff80080be574>] irq_exit+0xa8/0x100
> > > [ 12.295742] ---[ end trace e63cfc40c313ffab ]---
> > >
> > > The root of the problem is that the default segment size for sgt is
> > > (UINT_MAX & PAGE_MASK), and the default segment size for device dma is
> > > 64K. As such, if you compare the 2, you would deduce that the sg segment
> > > will overflow the device's capacity. In reality, the hardware can
> > > accommodate the larger sg segments, it's just not initializing its max
> > > segment properly. This patch initializes the max segment size for the
> > > mdss device, which gets rid of that pesky warning.
> > >
> > > Reported-by: Stephen Boyd <swboyd@chromium.org>
> > > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > > Tested-by: Stephen Boyd <swboyd@chromium.org>
> > > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > > ---
> > > This patch has been floating in the ether for over a year [1]. I know
> > > next to nothing about it, but I'm told it's still useful so I'm
> > > helpfully reposting it. Please enjoy.
> >
> > This looks like the right thing to do.. sorry I overlooked the patch
> > first time around
> >
> > Reviewed-by: Rob Clark <robdclark@gmail.com>
> >
> > (since I've already sent PR for msm-next, could we pick this up via drm-misc?)
>
> You got it, pushed to drm-misc-next-fixes.
>
thx
BR,
-R
> Thanks
>
> Sean
>
> >
> > BR,
> > -R
> >
> >
> > >
> > > [1] https://lore.kernel.org/r/20181106213239.52133-1-sean@poorly.run
> > >
> > > drivers/gpu/drm/msm/msm_drv.c | 8 ++++++++
> > > 1 file changed, 8 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> > > index c26219c7a49f..e4b750b0c2d3 100644
> > > --- a/drivers/gpu/drm/msm/msm_drv.c
> > > +++ b/drivers/gpu/drm/msm/msm_drv.c
> > > @@ -441,6 +441,14 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
> > > if (ret)
> > > goto err_msm_uninit;
> > >
> > > + if (!dev->dma_parms) {
> > > + dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
> > > + GFP_KERNEL);
> > > + if (!dev->dma_parms)
> > > + return -ENOMEM;
> > > + }
> > > + dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
> > > +
> > > msm_gem_shrinker_init(ddev);
> > >
> > > switch (get_mdp_ver(pdev)) {
> > > --
> > > 2.25.0.341.g760bfbb309-goog
> > >
>
> --
> Sean Paul, Software Engineer, Google / Chromium OS
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [REPOST PATCH] drm/msm: Set dma maximum segment size for mdss
@ 2020-01-22 15:43 ` Rob Clark
0 siblings, 0 replies; 10+ messages in thread
From: Rob Clark @ 2020-01-22 15:43 UTC (permalink / raw)
To: Sean Paul
Cc: saiprakash.ranjan, David Airlie, linux-arm-msm, Douglas Anderson,
dri-devel, Stephen Boyd, Matthias Kaehlcke, Sean Paul, freedreno,
Linux Kernel Mailing List
On Wed, Jan 22, 2020 at 6:51 AM Sean Paul <sean@poorly.run> wrote:
>
> On Tue, Jan 21, 2020 at 11:26:05AM -0800, Rob Clark wrote:
> > On Tue, Jan 21, 2020 at 11:19 AM Douglas Anderson <dianders@chromium.org> wrote:
> > >
> > > From: Sean Paul <seanpaul@chromium.org>
> > >
> > > Turning on CONFIG_DMA_API_DEBUG_SG results in the following error:
> > >
> > > [ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer than device claims to support [len=3526656] [max=65536]
> > > [ 12.089870] WARNING: CPU: 6 PID: 334 at /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301 debug_dma_map_sg+0x1dc/0x318
> > > [ 12.102655] Modules linked in: joydev
> > > [ 12.106442] CPU: 6 PID: 334 Comm: frecon Not tainted 4.19.0 #2
> > > [ 12.112450] Hardware name: Google Cheza (rev3+) (DT)
> > > [ 12.117566] pstate: 60400009 (nZCv daif +PAN -UAO)
> > > [ 12.122506] pc : debug_dma_map_sg+0x1dc/0x318
> > > [ 12.126995] lr : debug_dma_map_sg+0x1dc/0x318
> > > [ 12.131487] sp : ffffff800cc3ba80
> > > [ 12.134913] x29: ffffff800cc3ba80 x28: 0000000000000000
> > > [ 12.140395] x27: 0000000000000004 x26: 0000000000000004
> > > [ 12.145868] x25: ffffff8008e55b18 x24: 0000000000000000
> > > [ 12.151337] x23: 00000000ffffffff x22: ffffff800921c000
> > > [ 12.156809] x21: ffffffc0fa75b080 x20: ffffffc0f7195090
> > > [ 12.162280] x19: ffffffc0f1c53280 x18: 0000000000000000
> > > [ 12.167749] x17: 0000000000000000 x16: 0000000000000000
> > > [ 12.173218] x15: 0000000000000000 x14: 0720072007200720
> > > [ 12.178689] x13: 0720072007200720 x12: 0720072007200720
> > > [ 12.184161] x11: 0720072007200720 x10: 0720072007200720
> > > [ 12.189641] x9 : ffffffc0f1fc6b60 x8 : 0000000000000000
> > > [ 12.195110] x7 : ffffff8008132ce0 x6 : 0000000000000000
> > > [ 12.200585] x5 : 0000000000000000 x4 : ffffff8008134734
> > > [ 12.206058] x3 : ffffff800cc3b830 x2 : ffffffc0f1fc6240
> > > [ 12.211532] x1 : 25045a74f48a7400 x0 : 25045a74f48a7400
> > > [ 12.217006] Call trace:
> > > [ 12.219535] debug_dma_map_sg+0x1dc/0x318
> > > [ 12.223671] get_pages+0x19c/0x20c
> > > [ 12.227177] msm_gem_fault+0x64/0xfc
> > > [ 12.230874] __do_fault+0x3c/0x140
> > > [ 12.234383] __handle_mm_fault+0x70c/0xdb8
> > > [ 12.238603] handle_mm_fault+0xac/0xc4
> > > [ 12.242473] do_page_fault+0x1bc/0x3d4
> > > [ 12.246342] do_translation_fault+0x54/0x88
> > > [ 12.250652] do_mem_abort+0x60/0xf0
> > > [ 12.254250] el0_da+0x20/0x24
> > > [ 12.257317] irq event stamp: 67260
> > > [ 12.260828] hardirqs last enabled at (67259): [<ffffff8008132d0c>] console_unlock+0x214/0x608
> > > [ 12.269693] hardirqs last disabled at (67260): [<ffffff8008080e0c>] do_debug_exception+0x5c/0x178
> > > [ 12.278820] softirqs last enabled at (67256): [<ffffff8008081664>] __do_softirq+0x4d4/0x520
> > > [ 12.287510] softirqs last disabled at (67249): [<ffffff80080be574>] irq_exit+0xa8/0x100
> > > [ 12.295742] ---[ end trace e63cfc40c313ffab ]---
> > >
> > > The root of the problem is that the default segment size for sgt is
> > > (UINT_MAX & PAGE_MASK), and the default segment size for device dma is
> > > 64K. As such, if you compare the 2, you would deduce that the sg segment
> > > will overflow the device's capacity. In reality, the hardware can
> > > accommodate the larger sg segments, it's just not initializing its max
> > > segment properly. This patch initializes the max segment size for the
> > > mdss device, which gets rid of that pesky warning.
> > >
> > > Reported-by: Stephen Boyd <swboyd@chromium.org>
> > > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > > Tested-by: Stephen Boyd <swboyd@chromium.org>
> > > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > > ---
> > > This patch has been floating in the ether for over a year [1]. I know
> > > next to nothing about it, but I'm told it's still useful so I'm
> > > helpfully reposting it. Please enjoy.
> >
> > This looks like the right thing to do.. sorry I overlooked the patch
> > first time around
> >
> > Reviewed-by: Rob Clark <robdclark@gmail.com>
> >
> > (since I've already sent PR for msm-next, could we pick this up via drm-misc?)
>
> You got it, pushed to drm-misc-next-fixes.
>
thx
BR,
-R
> Thanks
>
> Sean
>
> >
> > BR,
> > -R
> >
> >
> > >
> > > [1] https://lore.kernel.org/r/20181106213239.52133-1-sean@poorly.run
> > >
> > > drivers/gpu/drm/msm/msm_drv.c | 8 ++++++++
> > > 1 file changed, 8 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> > > index c26219c7a49f..e4b750b0c2d3 100644
> > > --- a/drivers/gpu/drm/msm/msm_drv.c
> > > +++ b/drivers/gpu/drm/msm/msm_drv.c
> > > @@ -441,6 +441,14 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
> > > if (ret)
> > > goto err_msm_uninit;
> > >
> > > + if (!dev->dma_parms) {
> > > + dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
> > > + GFP_KERNEL);
> > > + if (!dev->dma_parms)
> > > + return -ENOMEM;
> > > + }
> > > + dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
> > > +
> > > msm_gem_shrinker_init(ddev);
> > >
> > > switch (get_mdp_ver(pdev)) {
> > > --
> > > 2.25.0.341.g760bfbb309-goog
> > >
>
> --
> Sean Paul, Software Engineer, Google / Chromium OS
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