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SubjectRe: [Patch v2 2/3] firmware: dmi_scan: use full dmi version for SMBIOS3
Hi Ivan,

Sorry for the very late review.

On Wed, 18 Feb 2015 13:33:20 +0200, Ivan Khoronzhuk wrote:
> New SMBIOS3 spec adds additional field for versioning - docrev.
> The docrev identifies the revision of a specification implemented in
> the table structures, so display SMBIOSv3 versions in format,
> like "3.22.1".

I'm not sure if that will be terribly useful in practice, but it
certainly can't hurt, so why not.

> In case of only 32 bit entry point for versions > 3 display
> dmi version like "3.22.x" as we don't know the docrev.
>
> In other cases display version like it was.

I don't like this part, see below.

> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
> ---
> drivers/firmware/dmi_scan.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
> index 07d2960..3f3470f 100644
> --- a/drivers/firmware/dmi_scan.c
> +++ b/drivers/firmware/dmi_scan.c
> @@ -17,7 +17,7 @@
> */
> static const char dmi_empty_string[] = " ";
>
> -static u16 __initdata dmi_ver;
> +static u32 dmi_ver __initdata;
> /*
> * Catch too early calls to dmi_check_system():
> */
> @@ -200,7 +200,7 @@ static void __init dmi_save_uuid(const struct dmi_header *dm, int slot,
> * the UUID are supposed to be little-endian encoded. The specification
> * says that this is the defacto standard.
> */
> - if (dmi_ver >= 0x0206)
> + if (dmi_ver >= 0x020600)
> sprintf(s, "%pUL", d);
> else
> sprintf(s, "%pUB", d);
> @@ -472,7 +472,7 @@ static void __init dmi_format_ids(char *buf, size_t len)
> */
> static int __init dmi_present(const u8 *buf)
> {
> - int smbios_ver;
> + u32 smbios_ver;

This makes little sense, as the code handles smbios_ver as a 16-bit
value. You should either leave this alone (this change is not needed
AFAICS?), or declare it as a u16. It only makes sense to make it a u32
if you change the code to store 24-bit values in it as you ultimately
do in dmi_ver.

>
> if (memcmp(buf, "_SM_", 4) == 0 &&
> buf[5] < 32 && dmi_checksum(buf, buf[5])) {
> @@ -507,8 +507,9 @@ static int __init dmi_present(const u8 *buf)
> if (dmi_walk_early(dmi_decode) == 0) {
> if (smbios_ver) {
> dmi_ver = smbios_ver;
> - pr_info("SMBIOS %d.%d present.\n",
> - dmi_ver >> 8, dmi_ver & 0xFF);
> + pr_info("SMBIOS %d.%d%s present.\n",
> + dmi_ver >> 8, dmi_ver & 0xFF,
> + (dmi_ver < 0x0300) ? "" : ".x");

I see zero value in this change. The trailing .x adds no information
for the reader, and if anyone tries to parse that line, this is more
work as they have 3 different formats to handle instead of 2.

> } else {
> smbios_header_size = 15;
> memcpy(smbios_header, buf, smbios_header_size);
> @@ -517,6 +518,7 @@ static int __init dmi_present(const u8 *buf)
> pr_info("Legacy DMI %d.%d present.\n",
> dmi_ver >> 8, dmi_ver & 0xFF);
> }
> + dmi_ver <<= 8;

I understand this was the easiest way to implement the change, but I'm
not really comfortable with dmi_ver having different formats for
different parts of the code. This is rather error prone for future
changes, even if the code is currently correct.

> dmi_format_ids(dmi_ids_string, sizeof(dmi_ids_string));
> printk(KERN_DEBUG "DMI: %s\n", dmi_ids_string);
> return 0;
> @@ -534,7 +536,8 @@ static int __init dmi_smbios3_present(const u8 *buf)
> {
> if (memcmp(buf, "_SM3_", 5) == 0 &&
> buf[6] < 32 && dmi_checksum(buf, buf[6])) {
> - dmi_ver = get_unaligned_be16(buf + 7);
> + dmi_ver = get_unaligned_be32(buf + 6);
> + dmi_ver &= 0xFFFFFF;

That would easily fit on a single line.

> dmi_len = get_unaligned_le32(buf + 12);
> dmi_base = get_unaligned_le64(buf + 16);
> smbios_header_size = buf[6];
> @@ -553,8 +556,9 @@ static int __init dmi_smbios3_present(const u8 *buf)
> dmi_num = dmi_len / 4;
>
> if (dmi_walk_early(dmi_decode) == 0) {
> - pr_info("SMBIOS %d.%d present.\n",
> - dmi_ver >> 8, dmi_ver & 0xFF);
> + pr_info("SMBIOS %d.%d.%d present.\n",
> + dmi_ver >> 16, (dmi_ver >> 8) & 0xFF,
> + dmi_ver & 0xFF);
> dmi_format_ids(dmi_ids_string, sizeof(dmi_ids_string));
> pr_debug("DMI: %s\n", dmi_ids_string);
> return 0;


--
Jean Delvare
SUSE L3 Support


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