Re: [PATCH v5 2/5] media: venus: vdec: AR50_LITE video core support

Dikshita Agarwal
2025-06-30T06:47:45Z

On 6/27/2025 8:48 PM, Jorge Ramirez wrote:
> On 27/06/25 18:17:27, Dikshita Agarwal wrote:
>>
>>
>> On 6/26/2025 7:29 PM, Jorge Ramirez-Ortiz wrote:
>>> The AR50_LITE is a streamlined variant of the AR50 video core, designed
>>> for power and cost-efficient platforms.
>>>
>>> It supports hardware-accelerated decoding of H.264, HEVC, and VP9
>>> formats.
>>>
>>> Co-developed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
>>> Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
>>> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>
>>> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
>>> ---
>>> drivers/media/platform/qcom/venus/core.c | 11 ++-
>>> drivers/media/platform/qcom/venus/core.h | 11 ++-
>>> drivers/media/platform/qcom/venus/firmware.c | 8 +-
>>> drivers/media/platform/qcom/venus/helpers.c | 80 +++++++++++++++++++
>>> drivers/media/platform/qcom/venus/helpers.h | 2 +
>>> .../media/platform/qcom/venus/hfi_helper.h | 10 ++-
>>> drivers/media/platform/qcom/venus/hfi_venus.c | 14 ++--
>>> .../media/platform/qcom/venus/pm_helpers.c | 1 +
>>> drivers/media/platform/qcom/venus/vdec.c | 15 ++--
>>> 9 files changed, 128 insertions(+), 24 deletions(-)
>>>
>>> diff --git a/drivers/media/platform/qcom/venus/core.c b/drivers/media/platform/qcom/venus/core.c
>>> index d305d74bb152..736ef53d988d 100644
>>> --- a/drivers/media/platform/qcom/venus/core.c
>>> +++ b/drivers/media/platform/qcom/venus/core.c
>>> @@ -254,14 +254,19 @@ static int venus_enumerate_codecs(struct venus_core *core, u32 type)
>>>
>>> static void venus_assign_register_offsets(struct venus_core *core)
>>> {
>>> - if (IS_IRIS2(core) || IS_IRIS2_1(core)) {
>>> - core->vbif_base = core->base + VBIF_BASE;
>>> + if (IS_IRIS2(core) || IS_IRIS2_1(core) || IS_AR50_LITE(core)) {
>>> core->cpu_base = core->base + CPU_BASE_V6;
>>> core->cpu_cs_base = core->base + CPU_CS_BASE_V6;
>>> core->cpu_ic_base = core->base + CPU_IC_BASE_V6;
>>> core->wrapper_base = core->base + WRAPPER_BASE_V6;
>>> core->wrapper_tz_base = core->base + WRAPPER_TZ_BASE_V6;
>>> - core->aon_base = core->base + AON_BASE_V6;
>>> + if (IS_AR50_LITE(core)) {
>>> + core->vbif_base = NULL;
>>> + core->aon_base = NULL;
>>> + } else {
>>> + core->vbif_base = core->base + VBIF_BASE;
>>> + core->aon_base = core->base + AON_BASE_V6;
>>> + }
>>> } else {
>>> core->vbif_base = core->base + VBIF_BASE;
>>> core->cpu_base = core->base + CPU_BASE;
>>> diff --git a/drivers/media/platform/qcom/venus/core.h b/drivers/media/platform/qcom/venus/core.h
>>> index b412e0c5515a..e755a28e919b 100644
>>> --- a/drivers/media/platform/qcom/venus/core.h
>>> +++ b/drivers/media/platform/qcom/venus/core.h
>>> @@ -382,6 +382,7 @@ enum venus_inst_modes {
>>> * @lock: instance lock
>>> * @core: a reference to the core struct
>>> * @clk_data: clock data per core ID
>>> + * @eosbufs: a lit of EOS buffers
>>> * @dpbbufs: a list of decoded picture buffers
>>> * @internalbufs: a list of internal bufferes
>>> * @registeredbufs: a list of registered capture bufferes
>>> @@ -450,6 +451,7 @@ struct venus_inst {
>>> struct mutex lock;
>>> struct venus_core *core;
>>> struct clock_data clk_data;
>>> + struct list_head eosbufs;
>>> struct list_head dpbbufs;
>>> struct list_head internalbufs;
>>> struct list_head registeredbufs;
>>> @@ -520,7 +522,14 @@ struct venus_inst {
>>> #define IS_V1(core) ((core)->res->hfi_version == HFI_VERSION_1XX)
>>> #define IS_V3(core) ((core)->res->hfi_version == HFI_VERSION_3XX)
>>> #define IS_V4(core) ((core)->res->hfi_version == HFI_VERSION_4XX)
>>> -#define IS_V6(core) ((core)->res->hfi_version == HFI_VERSION_6XX)
>>> +static inline bool IS_V6(struct venus_core *core)
>>> +{
>>> + if (WARN_ON_ONCE(!core))
>>> + return false;
>>> +
>>> + return core->res->hfi_version == HFI_VERSION_6XX ||
>>> + core->res->hfi_version == HFI_VERSION_6XX_LITE;
>>> +}
>> It should be HFI_VERSION_4XX_LITE for AR50_LITE. 4XX represents SC7280 and
>> SDM845 which are AR50.
>
> ah good information - where is this documented? I never found this
> information... I'd appreciate if you could confirm with some document
> for future reference.
>
>>>
>>> #define IS_AR50(core) ((core)->res->vpu_version == VPU_VERSION_AR50)
>>> #define IS_AR50_LITE(core) ((core)->res->vpu_version == VPU_VERSION_AR50_LITE)
>>> diff --git a/drivers/media/platform/qcom/venus/firmware.c b/drivers/media/platform/qcom/venus/firmware.c
>>> index 66a18830e66d..f8dcef0426ac 100644
>>> --- a/drivers/media/platform/qcom/venus/firmware.c
>>> +++ b/drivers/media/platform/qcom/venus/firmware.c
>>> @@ -30,7 +30,7 @@ static void venus_reset_cpu(struct venus_core *core)
>>> u32 fw_size = core->fw.mapped_mem_size;
>>> void __iomem *wrapper_base;
>>>
>>> - if (IS_IRIS2_1(core))
>>> + if (IS_IRIS2_1(core) || IS_AR50_LITE(core))
>>> wrapper_base = core->wrapper_tz_base;
>>> else
>>> wrapper_base = core->wrapper_base;
>>> @@ -42,7 +42,7 @@ static void venus_reset_cpu(struct venus_core *core)
>>> writel(fw_size, wrapper_base + WRAPPER_NONPIX_START_ADDR);
>>> writel(fw_size, wrapper_base + WRAPPER_NONPIX_END_ADDR);
>>>
>>> - if (IS_IRIS2_1(core)) {
>>> + if (IS_IRIS2_1(core) || IS_AR50_LITE(core)) {
>>> /* Bring XTSS out of reset */
>>> writel(0, wrapper_base + WRAPPER_TZ_XTSS_SW_RESET);
>>> } else {
>>> @@ -68,7 +68,7 @@ int venus_set_hw_state(struct venus_core *core, bool resume)
>>> if (resume) {
>>> venus_reset_cpu(core);
>>> } else {
>>> - if (IS_IRIS2_1(core))
>>> + if (IS_IRIS2_1(core) || IS_AR50_LITE(core))
>>> writel(WRAPPER_XTSS_SW_RESET_BIT,
>>> core->wrapper_tz_base + WRAPPER_TZ_XTSS_SW_RESET);
>>> else
>>> @@ -181,7 +181,7 @@ static int venus_shutdown_no_tz(struct venus_core *core)
>>> void __iomem *wrapper_base = core->wrapper_base;
>>> void __iomem *wrapper_tz_base = core->wrapper_tz_base;
>>>
>>> - if (IS_IRIS2_1(core)) {
>>> + if (IS_IRIS2_1(core) || IS_AR50_LITE(core)) {
>>> /* Assert the reset to XTSS */
>>> reg = readl(wrapper_tz_base + WRAPPER_TZ_XTSS_SW_RESET);
>> No need to handle no-tz case. Pls drop.
>
> ok
>
>>> reg |= WRAPPER_XTSS_SW_RESET_BIT;
>>> diff --git a/drivers/media/platform/qcom/venus/helpers.c b/drivers/media/platform/qcom/venus/helpers.c
>>> index 8295542e1a7c..812bec9a05be 100644
>>> --- a/drivers/media/platform/qcom/venus/helpers.c
>>> +++ b/drivers/media/platform/qcom/venus/helpers.c
>>> @@ -230,6 +230,79 @@ int venus_helper_alloc_dpb_bufs(struct venus_inst *inst)
>>> }
>>> EXPORT_SYMBOL_GPL(venus_helper_alloc_dpb_bufs);
>>>
>>> +static void free_eos_buf(struct venus_inst *inst, struct intbuf *buf)
>>> +{
>>> + list_del_init(&buf->list);
>>> + dma_free_attrs(inst->core->dev, buf->size, buf->va, buf->da,
>>> + buf->attrs);
>>> + kfree(buf);
>>> +}
>>> +
>>> +int venus_helper_free_eos_bufs(struct venus_inst *inst)
>>> +{
>>> + struct intbuf *buf, *n;
>>> +
>>> + list_for_each_entry_safe(buf, n, &inst->eosbufs, list) {
>>> + free_eos_buf(inst, buf);
>>> + }
>>> +
>>> + if (list_empty(&inst->eosbufs))
>>> + INIT_LIST_HEAD(&inst->eosbufs);
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(venus_helper_free_eos_bufs);
>>> +
>>> +int venus_helper_alloc_eos_buf(struct venus_inst *inst,
>>> + struct hfi_frame_data *data)
>>> +{
>>> + struct venus_core *core = inst->core;
>>> + struct device *dev = core->dev;
>>> + struct intbuf *buf;
>>> + int ret = 0;
>>> +
>>> + memset(data, 0, sizeof(*data));
>>> +
>>> + data->buffer_type = HFI_BUFFER_INPUT;
>>> + data->flags = HFI_BUFFERFLAG_EOS;
>>> +
>>> + if (IS_AR50_LITE(inst->core)) {
>>> + /* We must send valid sizes and addresses */
>>> + buf = kzalloc(sizeof(*buf), GFP_KERNEL);
>>> + if (!buf) {
>>> + ret = -ENOMEM;
>>> + goto fail;
>>> + }
>>> +
>>> + buf->type = HFI_BUFFER_INPUT;
>>> + buf->size = SZ_4K;
>>> + buf->attrs = DMA_ATTR_NO_KERNEL_MAPPING;
>>> + buf->va = dma_alloc_attrs(dev, buf->size, &buf->da, GFP_KERNEL,
>>> + buf->attrs);
>>> + if (!buf->va) {
>>> + ret = -ENOMEM;
>>> + goto fail;
>>> + }
>>> +
>>> + list_add_tail(&buf->list, &inst->eosbufs);
>>> +
>>> + data->alloc_len = buf->size;
>>> + data->device_addr = buf->da;
>>> +
>> why this special handling for eos buffer is needed for AR50_LITE?
>
> this _fix_ was develope through testing: without it there is no EOS and
> errors are reporting upon killing the player
>
Would be better to see why there is no EOS from firmware,
there shouldn't be the need to have a dma allocation for this dummy
buffers, as there is no useful info in the buffer. Having the device
address as 0 or 0xdeadb000 should be enough.

>
>>> + } else if (IS_V6(inst->core) &&
>>> + is_fw_rev_or_older(inst->core, 1, 0, 87)) {
>>> + data->device_addr = 0;
>>> + } else {
>>> + data->device_addr = 0xdeadb000;
>>> + }
>>> +
>>> + return 0;
>>> +fail:
>>> + kfree(buf);
>>> + return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(venus_helper_alloc_eos_buf);
>>> +
>>> static int intbufs_set_buffer(struct venus_inst *inst, u32 type)
>>> {
>>> struct venus_core *core = inst->core;
>>> @@ -630,6 +703,13 @@ static int platform_get_bufreq(struct venus_inst *inst, u32 buftype,
>>> if (!hfi_plat || !hfi_plat->bufreq)
>>> return -EINVAL;
>>>
>>> + /* Firmware buffer requirements for internal buffers only */
>>> + if (IS_AR50_LITE(inst->core))
>>> + if (buftype != HFI_BUFFER_INPUT &&
>>> + buftype != HFI_BUFFER_OUTPUT &&
>>> + buftype != HFI_BUFFER_OUTPUT2)
>>> + return -EINVAL;
>>> +
>> why this check is needed here? Buffer requirements for all buffer types
>> should come from firmware for all V4 based targets.
>
> because I used V6 as you saw earlier.
Yes, pls use v4, and in that case all buffer requirements will come from
firmware.

Thanks,
Dikshita
>
>>> params.version = version;
>>> params.num_vpp_pipes = inst->core->res->num_vpp_pipes;
>>>
>>> diff --git a/drivers/media/platform/qcom/venus/helpers.h b/drivers/media/platform/qcom/venus/helpers.h
>>> index 358e4f39c9c0..bf55fe3b8747 100644
>>> --- a/drivers/media/platform/qcom/venus/helpers.h
>>> +++ b/drivers/media/platform/qcom/venus/helpers.h
>>> @@ -58,6 +58,8 @@ int venus_helper_get_out_fmts(struct venus_inst *inst, u32 fmt, u32 *out_fmt,
>>> bool venus_helper_check_format(struct venus_inst *inst, u32 v4l2_pixfmt);
>>> int venus_helper_alloc_dpb_bufs(struct venus_inst *inst);
>>> int venus_helper_free_dpb_bufs(struct venus_inst *inst);
>>> +int venus_helper_alloc_eos_buf(struct venus_inst *inst, struct hfi_frame_data *data);
>>> +int venus_helper_free_eos_bufs(struct venus_inst *inst);
>>> int venus_helper_intbufs_alloc(struct venus_inst *inst);
>>> int venus_helper_intbufs_free(struct venus_inst *inst);
>>> int venus_helper_intbufs_realloc(struct venus_inst *inst);
>>> diff --git a/drivers/media/platform/qcom/venus/hfi_helper.h b/drivers/media/platform/qcom/venus/hfi_helper.h
>>> index f44059f19505..128ddf8e3cd5 100644
>>> --- a/drivers/media/platform/qcom/venus/hfi_helper.h
>>> +++ b/drivers/media/platform/qcom/venus/hfi_helper.h
>>> @@ -397,13 +397,16 @@
>>> #define HFI_BUFFER_INTERNAL_PERSIST_1 0x5
>>> #define HFI_BUFFER_INTERNAL_SCRATCH(ver) \
>>> (((ver) == HFI_VERSION_4XX || \
>>> - (ver) == HFI_VERSION_6XX) ? 0x6 : 0x1000001)
>>> + (ver) == HFI_VERSION_6XX || (ver) == HFI_VERSION_6XX_LITE) \
>>> + ? 0x6 : 0x1000001)
>>> #define HFI_BUFFER_INTERNAL_SCRATCH_1(ver) \
>>> (((ver) == HFI_VERSION_4XX || \
>>> - (ver) == HFI_VERSION_6XX) ? 0x7 : 0x1000005)
>>> + (ver) == HFI_VERSION_6XX || (ver) == HFI_VERSION_6XX_LITE) \
>>> + ? 0x7 : 0x1000005)
>>> #define HFI_BUFFER_INTERNAL_SCRATCH_2(ver) \
>>> (((ver) == HFI_VERSION_4XX || \
>>> - (ver) == HFI_VERSION_6XX) ? 0x8 : 0x1000006)
>>> + (ver) == HFI_VERSION_6XX || (ver) == HFI_VERSION_6XX_LITE) \
>>> + ? 0x8 : 0x1000006)
>>> #define HFI_BUFFER_EXTRADATA_INPUT(ver) \
>>> (((ver) == HFI_VERSION_4XX) ? 0xc : 0x1000002)
>>> #define HFI_BUFFER_EXTRADATA_OUTPUT(ver) \
>>> @@ -561,6 +564,7 @@ enum hfi_version {
>>> HFI_VERSION_3XX,
>>> HFI_VERSION_4XX,
>>> HFI_VERSION_6XX,
>>> + HFI_VERSION_6XX_LITE,
>> s/HFI_VERSION_6XX_LITE/HFI_VERSION_4XX_LITE.
>> update all applicable places.
>
> sure, I'll validate that - I remember starting with V4 but it didnt
> work so switched to 6xx. I'll try again.
>
>
>>> };
>>>
>>> struct hfi_buffer_info {
>>> diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c b/drivers/media/platform/qcom/venus/hfi_venus.c
>>> index b5f2ea879950..302776bf8fe6 100644
>>> --- a/drivers/media/platform/qcom/venus/hfi_venus.c
>>> +++ b/drivers/media/platform/qcom/venus/hfi_venus.c
>>> @@ -497,7 +497,7 @@ static int venus_boot_core(struct venus_hfi_device *hdev)
>>> if (count >= max_tries)
>>> ret = -ETIMEDOUT;
>>>
>>> - if (IS_IRIS2(hdev->core) || IS_IRIS2_1(hdev->core)) {
>>> + if (IS_IRIS2(hdev->core) || IS_IRIS2_1(hdev->core) || IS_AR50_LITE(hdev->core)) {
>>> writel(0x1, cpu_cs_base + CPU_CS_H2XSOFTINTEN_V6);
>>> writel(0x0, cpu_cs_base + CPU_CS_X2RPMH_V6);
>> CPU_CS_X2RPMH_V6 is not needed for AR50_LITE, pls drop.
>>> }
>>> @@ -565,6 +565,9 @@ static int venus_halt_axi(struct venus_hfi_device *hdev)
>>> u32 mask_val;
>>> int ret;
>>>
>>> + if (IS_AR50_LITE(hdev->core))
>>> + return 0;
>>> +
>>> if (IS_IRIS2(hdev->core) || IS_IRIS2_1(hdev->core)) {
>>> writel(0x3, cpu_cs_base + CPU_CS_X2RPMH_V6);
>>>
>>> @@ -1134,7 +1137,8 @@ static irqreturn_t venus_isr(struct venus_core *core)
>>> wrapper_base = hdev->core->wrapper_base;
>>>
>>> status = readl(wrapper_base + WRAPPER_INTR_STATUS);
>>> - if (IS_IRIS2(core) || IS_IRIS2_1(core)) {
>>> +
>>> + if (IS_IRIS2(core) || IS_IRIS2_1(core) || IS_AR50_LITE(core)) {
>>> if (status & WRAPPER_INTR_STATUS_A2H_MASK ||
>>> status & WRAPPER_INTR_STATUS_A2HWD_MASK_V6 ||
>> WD mask is incorrect, pls fix.
>>> status & CPU_CS_SCIACMDARG0_INIT_IDLE_MSG_MASK)
>>> @@ -1146,7 +1150,7 @@ static irqreturn_t venus_isr(struct venus_core *core)
>>> hdev->irq_status = status;
>>> }
>>> writel(1, cpu_cs_base + CPU_CS_A2HSOFTINTCLR);
>>> - if (!(IS_IRIS2(core) || IS_IRIS2_1(core)))
>>> + if (!(IS_IRIS2(core) || IS_IRIS2_1(core) || IS_AR50_LITE(core)))
>>> writel(status, wrapper_base + WRAPPER_INTR_CLEAR);
>>>
>>> return IRQ_WAKE_THREAD;
>>> @@ -1531,7 +1535,7 @@ static bool venus_cpu_and_video_core_idle(struct venus_hfi_device *hdev)
>>> void __iomem *cpu_cs_base = hdev->core->cpu_cs_base;
>>> u32 ctrl_status, cpu_status;
>>>
>>> - if (IS_IRIS2(hdev->core) || IS_IRIS2_1(hdev->core))
>>> + if (IS_IRIS2(hdev->core) || IS_IRIS2_1(hdev->core) || IS_AR50_LITE(hdev->core))
>>> cpu_status = readl(wrapper_tz_base + WRAPPER_TZ_CPU_STATUS_V6);
>>> else
>>> cpu_status = readl(wrapper_base + WRAPPER_CPU_STATUS);
>>> @@ -1551,7 +1555,7 @@ static bool venus_cpu_idle_and_pc_ready(struct venus_hfi_device *hdev)
>>> void __iomem *cpu_cs_base = hdev->core->cpu_cs_base;
>>> u32 ctrl_status, cpu_status;
>>>
>>> - if (IS_IRIS2(hdev->core) || IS_IRIS2_1(hdev->core))
>>> + if (IS_IRIS2(hdev->core) || IS_IRIS2_1(hdev->core) || IS_AR50_LITE(hdev->core))
>>> cpu_status = readl(wrapper_tz_base + WRAPPER_TZ_CPU_STATUS_V6);
>>> else
>>> cpu_status = readl(wrapper_base + WRAPPER_CPU_STATUS);
>>> diff --git a/drivers/media/platform/qcom/venus/pm_helpers.c b/drivers/media/platform/qcom/venus/pm_helpers.c
>>> index 409aa9bd0b5d..5d9dfe3fd043 100644
>>> --- a/drivers/media/platform/qcom/venus/pm_helpers.c
>>> +++ b/drivers/media/platform/qcom/venus/pm_helpers.c
>>> @@ -1168,6 +1168,7 @@ const struct venus_pm_ops *venus_pm_get(enum hfi_version version)
>>> return &pm_ops_v3;
>>> case HFI_VERSION_4XX:
>>> case HFI_VERSION_6XX:
>>> + case HFI_VERSION_6XX_LITE:
>> s/HFI_VERSION_6XX_LITE/HFI_VERSION_4XX_LITE
>
> yep
>
>>
>> Thanks,
>> Dikshita
>>> return &pm_ops_v4;
>>> }
>>>
>>> diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c
>>> index 99ce5fd41577..87c7901b280e 100644
>>> --- a/drivers/media/platform/qcom/venus/vdec.c
>>> +++ b/drivers/media/platform/qcom/venus/vdec.c
>>> @@ -550,7 +550,7 @@ vdec_decoder_cmd(struct file *file, void *fh, struct v4l2_decoder_cmd *cmd)
>>> {
>>> struct venus_inst *inst = to_inst(file);
>>> struct vb2_queue *dst_vq;
>>> - struct hfi_frame_data fdata = {0};
>>> + struct hfi_frame_data fdata;
>>> int ret;
>>>
>>> ret = v4l2_m2m_ioctl_try_decoder_cmd(file, fh, cmd);
>>> @@ -561,18 +561,15 @@ vdec_decoder_cmd(struct file *file, void *fh, struct v4l2_decoder_cmd *cmd)
>>>
>>> if (cmd->cmd == V4L2_DEC_CMD_STOP) {
>>> /*
>>> - * Implement V4L2_DEC_CMD_STOP by enqueue an empty buffer on
>>> + * Implement V4L2_DEC_CMD_STOP by enqueue a buffer on
>>> * decoder input to signal EOS.
>>> */
>>> if (!(inst->streamon_out && inst->streamon_cap))
>>> goto unlock;
>>>
>>> - fdata.buffer_type = HFI_BUFFER_INPUT;
>>> - fdata.flags |= HFI_BUFFERFLAG_EOS;
>>> - if (IS_V6(inst->core) && is_fw_rev_or_older(inst->core, 1, 0, 87))
>>> - fdata.device_addr = 0;
>>> - else
>>> - fdata.device_addr = 0xdeadb000;
>>> + ret = venus_helper_alloc_eos_buf(inst, &fdata);
>>> + if (ret)
>>> + goto unlock;
>>>
>>> ret = hfi_session_process_buf(inst, &fdata);
>>>
>>> @@ -1332,6 +1329,7 @@ static void vdec_session_release(struct venus_inst *inst)
>>> hfi_session_abort(inst);
>>>
>>> venus_helper_free_dpb_bufs(inst);
>>> + venus_helper_free_eos_bufs(inst);
>>> venus_pm_load_scale(inst);
>>> INIT_LIST_HEAD(&inst->registeredbufs);
>>> mutex_unlock(&inst->lock);
>>> @@ -1682,6 +1680,7 @@ static int vdec_open(struct file *file)
>>> if (!inst)
>>> return -ENOMEM;
>>>
>>> + INIT_LIST_HEAD(&inst->eosbufs);
>>> INIT_LIST_HEAD(&inst->dpbbufs);
>>> INIT_LIST_HEAD(&inst->registeredbufs);
>>> INIT_LIST_HEAD(&inst->internalbufs);