| From 52449be554ee061e1ebf69d42856d630d73f3e8b Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 21 Jan 2020 11:18:48 -0800 |
| Subject: drm/msm: Set dma maximum segment size for mdss |
| |
| From: Sean Paul <seanpaul@chromium.org> |
| |
| [ Upstream commit db735fc4036bbe1fbe606819b5f0ff26cc76cdff ] |
| |
| 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> |
| Tested-by: Stephen Boyd <swboyd@chromium.org> |
| Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> |
| Reviewed-by: Rob Clark <robdclark@gmail.com> |
| Signed-off-by: Sean Paul <seanpaul@chromium.org> |
| Signed-off-by: Douglas Anderson <dianders@chromium.org> |
| Link: https://patchwork.freedesktop.org/patch/msgid/20200121111813.REPOST.1.I92c66a35fb13f368095b05287bdabdbe88ca6922@changeid |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| 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 c84f0a8b3f2ce..b73fbb65e14b2 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)) { |
| -- |
| 2.20.1 |
| |