Re: [PATCH v9 02/19] media: iris: Add Gen2 firmware autodetect and fallback

[Vikash Garodia]

On 9/24/2026 6:06 PM, Bryan O'Donoghue wrote:
> On 31/07/2026 00:48, Dmitry Baryshkov wrote:
> > +
> > +/*
> > + * Detect the firmware generation and publish the descriptor. Run 
> > only after
> > + * qcom_mdt_load() has succeeded, so the driver commits to a HFI 
> > generation
> > + * only for a firmware image that has actually been loaded.
> > + *
> > + * The generation is detected from the loaded image (@data / @size 
> > point at the
> > + * reserved memory region populated by qcom_mdt_load()) rather than 
> > from the
> > + * request_firmware() blob: for a split .mdt the latter holds only 
> > the ELF
> > + * headers, while QC_IMAGE_VERSION_STRING lives in the .bNN data 
> > segments.
> > + *
> > + * The descriptor and firmware data are published exactly once, 
> > before any
> > + * session exists, so the lockless readers in the ioctl paths never 
> > observe a
> > + * reassignment. Later bring-ups reuse the already published descriptor.
> > + */
> > +static void iris_detect_firmware(struct iris_core *core, const char 
> > *fw_name,
> > +                 const u8 *data, size_t size,
> > +                 const struct iris_firmware_desc *desc)
> > +{
> > +    if (core->iris_firmware_desc)
> > +        return;
> > +
> > +    /*
> > +     * With a DT firmware-name override on a dual-generation platform 
> > the
> > +     * image on disk decides the generation, so inspect it and switch 
> > to the
> > +     * Gen1 descriptor when a Gen1 image was loaded.
> > +     */
> > +    if (desc == core->iris_platform_data->firmware_desc_gen2 &&
> > +        core->iris_platform_data->firmware_desc_gen1 &&
> > +        of_property_present(dev_of_node(core->dev), "firmware-name") &&
> > +        !iris_detect_gen2_from_fwdata(data, size)) {
> > +        dev_info(core->dev, "Gen1 FW detected in %s\n", fw_name);
> > +        desc = core->iris_platform_data->firmware_desc_gen1;
> > +    }
> > +
> > +    /* Publish iris_firmware_data first, then iris_firmware_desc (the 
> > guard). */
> > +    core->iris_firmware_data = desc->firmware_data;
> > +    core->iris_firmware_desc = desc;
> > +}
> > +
>
> In function ‘iris_detect_firmware’,
>      inlined from ‘iris_load_fw_to_memory’ at drivers/media/platform/ 
> qcom/iris/iris_firmware.c:216:3:
> drivers/media/platform/qcom/iris/iris_firmware.c:161:12: warning: ‘desc’ 
> may be used uninitialized [-Wmaybe-uninitialized]
>    161 |         if (desc == core->iris_platform_data- 
>  >firmware_desc_gen2 &&
>        |            ^
> drivers/media/platform/qcom/iris/iris_firmware.c: In function 
> ‘iris_load_fw_to_memory’:
> drivers/media/platform/qcom/iris/iris_firmware.c:176:42: note: ‘desc’ 
> was declared here
>    176 |         const struct iris_firmware_desc *desc;
>        |                                          ^~~~
> In function ‘iris_detect_firmware’,
>      inlined from ‘iris_load_fw_to_memory’ at drivers/media/platform/ 
> qcom/iris/iris_firmware.c:216:3:
> drivers/media/platform/qcom/iris/iris_firmware.c:170:40: warning: ‘desc’ 
> may be used uninitialized [-Wmaybe-uninitialized]
>    170 |         core->iris_firmware_data = desc->firmware_data;
>        |                                    ~~~~^~~~~~~~~~~~~~~
> drivers/media/platform/qcom/iris/iris_firmware.c: In function 
> ‘iris_load_fw_to_memory’:
> drivers/media/platform/qcom/iris/iris_firmware.c:176:42: note: ‘desc’ 
> was declared here
>    176 |         const struct iris_firmware_desc *desc;
>        |                                          ^~~~
> . "$TS_DIR"/lib/common-end.sh
> #!/bin/sh
> # Copyright 2024 Google LLC
>
> Proposed fix
>
> ╰─$ git diff
> diff --git a/drivers/media/platform/qcom/iris/iris_firmware.c b/drivers/ 
> media/platform/qcom/iris/iris_firmware.c
> index dfc4c184646c6..39558a300d38c 100644
> --- a/drivers/media/platform/qcom/iris/iris_firmware.c
> +++ b/drivers/media/platform/qcom/iris/iris_firmware.c
> @@ -153,6 +153,9 @@ static void iris_detect_firmware(struct iris_core 
> *core, const char *fw_name,
>         if (core->iris_firmware_desc)
>                 return;
>
> +      if (!desc)
> +              return;
> +

Reviewed-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>