Re: brcmfmac build failure with gcc < 4.3 due to __UNIQUE_ID() clash

Geert Uytterhoeven [off-list ref] writes:

On Wed, Jan 13, 2016 at 5:55 AM, Linux Kernel Mailing List
[off-list ref] wrote:

quoted

Commit:     46d703a775394e4724509ff55cdda41d228c028c
   brcmfmac: Unify methods to define and map firmware files.

[...]

This change breaks the build with gcc < 4.3:

    drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:598:
error: redefinition of ‘__UNIQUE_ID_firmware598’
    drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:598:
error: previous definition of ‘__UNIQUE_ID_firmware598’ was here
    drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:599:
error: redefinition of ‘__UNIQUE_ID_firmware600’
    drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:599:
error: previous definition of ‘__UNIQUE_ID_firmware600’ was here
    ...

The reason is that BRCMF_FW_NVRAM_DEF() expands to two instances of
MODULE_FIRMWARE():

quoted

--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.h
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.h

+#define BRCMF_FW_NVRAM_DEF(fw_nvram_name, fw, nvram) \
+static const char BRCM_ ## fw_nvram_name ## _FIRMWARE_NAME[] = \
+       BRCMF_FW_DEFAULT_PATH fw; \
+static const char BRCM_ ## fw_nvram_name ## _NVRAM_NAME[] = \
+       BRCMF_FW_DEFAULT_PATH nvram; \
+MODULE_FIRMWARE(BRCMF_FW_DEFAULT_PATH fw); \
+MODULE_FIRMWARE(BRCMF_FW_DEFAULT_PATH nvram)

When compiling using gcc < 4.3, __UNIQUE_ID() uses __LINE__ instead of
__COUNTER__, as the latter is not available. Hence it derives a "unique" ID
from the same source line number, causing a redefinition.

Hante, what should we do? We need to fix this build breakage ASAP.

-- 
Kalle Valo