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Subject: Re: [PATCH v2] drm/sun4i: Add DMA mask and segment size
To:     Jernej Skrabec <jernej.skrabec@gmail.com>, mripard@kernel.org,
        wens@csie.org
Cc:     airlied@linux.ie, daniel@ffwll.ch, dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev,
        linux-kernel@vger.kernel.org
References: <20220620181333.650301-1-jernej.skrabec@gmail.com>
From:   Samuel Holland <samuel@sholland.org>
Message-ID: <4c0c9c77-260a-9955-46bd-1740cdf8c22c@sholland.org>
Date:   Mon, 20 Jun 2022 22:17:19 -0500
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On 6/20/22 1:13 PM, Jernej Skrabec wrote:
> Kernel occasionally complains that there is mismatch in segment size
> when trying to render HW decoded videos and rendering them directly with
> sun4i DRM driver. Following message can be observed on H6 SoC:
> 
> [  184.298308] ------------[ cut here ]------------
> [  184.298326] DMA-API: sun4i-drm display-engine: mapping sg segment longer than device claims to support [len=6144000] [max=65536]
> [  184.298364] WARNING: CPU: 1 PID: 382 at kernel/dma/debug.c:1162 debug_dma_map_sg+0x2b0/0x350
> [  184.322997] CPU: 1 PID: 382 Comm: ffmpeg Not tainted 5.19.0-rc1+ #1331
> [  184.329533] Hardware name: Tanix TX6 (DT)
> [  184.333544] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [  184.340512] pc : debug_dma_map_sg+0x2b0/0x350
> [  184.344882] lr : debug_dma_map_sg+0x2b0/0x350
> [  184.349250] sp : ffff800009f33a50
> [  184.352567] x29: ffff800009f33a50 x28: 0000000000010000 x27: ffff000001b86c00
> [  184.359725] x26: ffffffffffffffff x25: ffff000005d8cc80 x24: 0000000000000000
> [  184.366879] x23: ffff80000939ab18 x22: 0000000000000001 x21: 0000000000000001
> [  184.374031] x20: 0000000000000000 x19: ffff0000018a7410 x18: ffffffffffffffff
> [  184.381186] x17: 0000000000000000 x16: 0000000000000000 x15: ffffffffffffffff
> [  184.388338] x14: 0000000000000001 x13: ffff800009534e86 x12: 6f70707573206f74
> [  184.395493] x11: 20736d69616c6320 x10: 000000000000000a x9 : 0000000000010000
> [  184.402647] x8 : ffff8000093b6d40 x7 : ffff800009f33850 x6 : 000000000000000c
> [  184.409800] x5 : ffff0000bf997940 x4 : 0000000000000000 x3 : 0000000000000027
> [  184.416953] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000003960e80
> [  184.424106] Call trace:
> [  184.426556]  debug_dma_map_sg+0x2b0/0x350
> [  184.430580]  __dma_map_sg_attrs+0xa0/0x110
> [  184.434687]  dma_map_sgtable+0x28/0x4c
> [  184.438447]  vb2_dc_dmabuf_ops_map+0x60/0xcc
> [  184.442729]  __map_dma_buf+0x2c/0xd4
> [  184.446321]  dma_buf_map_attachment+0xa0/0x130
> [  184.450777]  drm_gem_prime_import_dev+0x7c/0x18c
> [  184.455410]  drm_gem_prime_fd_to_handle+0x1b8/0x214
> [  184.460300]  drm_prime_fd_to_handle_ioctl+0x2c/0x40
> [  184.465190]  drm_ioctl_kernel+0xc4/0x174
> [  184.469123]  drm_ioctl+0x204/0x420
> [  184.472534]  __arm64_sys_ioctl+0xac/0xf0
> [  184.476474]  invoke_syscall+0x48/0x114
> [  184.480240]  el0_svc_common.constprop.0+0x44/0xec
> [  184.484956]  do_el0_svc+0x2c/0xc0
> [  184.488283]  el0_svc+0x2c/0x84
> [  184.491354]  el0t_64_sync_handler+0x11c/0x150
> [  184.495723]  el0t_64_sync+0x18c/0x190
> [  184.499397] ---[ end trace 0000000000000000 ]---
> 
> Fix that by setting DMA mask and segment size.
> 
> Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Reviewed-by: Samuel Holland <samuel@sholland.org>