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

[Bryan O'Donoghue <bryan.odonoghue@linaro.org>]

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;
+
        /*
         * 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